In a heartbreakingly open interview, the mum-of-two has told how she sat on a toilet seat clutching rosary beads and trying to find a way to go on.
And Majella has now revealed how she has resigned herself to taking anti-depressants for the rest of her life to cope with her illness.
She even ended up desperately contacting social services to help her care for her three year old daughter, Siobhan, during one of her blackest periods.
The 50 year old, who divides her time with husband Daniel between Kincasslagh and Tenerife, says she is now on top of the world but she has learned she needs medication to treat her disease.
She revealed she first had suicidal thoughts when her marriage was falling apart in England in the early nineties.
“It is the most dreadful disease you could possibly have. You are in this hole and it’s way, way down and everyone else is at the top. Nobody can do anything for you, absolutely nobody.
“You hear people who have committed suicide and people saying ‘why didn’t they come to me?’
“But you genuinely believe the world would be much better without you including your children. I did with mine.
“I just thought so many times I’m better off out of this. I did consider (suicide) numerous times but I didn’t have the guts to go through with it.
“I had it since my teens and early twenties but I didn’t get medication. I read books and went to see a psychologist and tried positive affirmations.
“I went to the doctor and told him I couldn’t be depressed because I was a positive thinker and I read books.
“He said ‘Majella, it’s like saying I can’t have blood pressure because I’ve read books’.
“He said it was a chemical imbalance and I needed something to balance it. I haven’t been (depressed) since I started taking the anti-depressants. Thanks be to God. I was very lucky and they worked great for me.”
She said she decided to wean herself off her tablets shortly after marrying Daniel but the depression returned.
She said: “After I married I thought ‘This is fantastic. I have no more worries, I love this man to bits, he loves me. We’ve a great life. Surely to God I don’t need these’.
“I start to wean myself of them slowly, slowly but surely. I remember Daniel was in the middle of a really big tour in England and I hit the bottom again.
“I found myself with a pair of rosary beads sitting on a toilet at half past four in the morning in a hotel in London rocking back and forth and crying and praying.
“I said ‘Please God don’t let me go down there again.’ Daniel just said then ‘Please go back on them and don’t ever come off them again’.
“I don’t think I will. I think that’s it for life.”
She said one of her worst times was shortly after the birth of her son Michael when her marriage was on the rocks.
She said: “I can remember very, very clearly sitting in the toilet at home which was locked and rocking back and forth with the baby.
“My daughter (Siobhan), who was almost three, was saying ‘Mammy, Mammy, let me in’. I was thinking ‘go away, leave us alone’.
“I couldn’t cope with anyone demanding anything of me. He was young and was only a few months old so he didn’t demand as in asking.
“I phoned up child services and asked if someone please come and help me with this child. She went out to a woman who looked after her from 9 to 5 to give me the break.
“They did that for about three or four months I think. Then I started to come around after that.
“I didn’t have any family there (in England). My family were my ex’s family and I couldn’t phone them with the whole thing.”
During the interview, she told of her deep sadness that her first marriage ended in divorce.
“We were together for 8 or 9 years. We had two children. My daughter Siobhan is 23 and my son, Michael, is 20.
“When it ended I was absolutely devastated. I used to think every single day I was so lucky to have this guy.
“He was a lovely guy but unfortunately he did have a wandering streak in him and there was lots of affairs and I tried to work through lots of them and in the end I thought I can’t do this anymore.
“I was devastated because this was the person I was going to grow old with. This was the father of my children.
“My son was 3 and my daughter was 5 and I’d say I was in a very, very bad place for a good four years.
“I really, really never wanted to be a divorcee. I still to this day, much as I absolutely love Daniel and he’s a far better partner and person for me, I still wish I was with the father of my children.
“I don’t mean that person, just that I was with the father of my children.
It would be so much easier and it’s so lovely to have your 50th anniversary with your children there.
“It just complicated everything if there is another person involved but that’s life.”
After her children went to boarding school she moved to Tenerife to be near her parents and ended up meeting her famous husband.
She said: “A mutual friend of ours introduced me to him and we got chatting. I thought he was lovely. I never thought of it as a romantic thing funny enough.
“I was divorced with two children and it wasn’t on my mind. I just thought he as lovely guy and then he asked me to go the next night. I thought ‘Jesus Christ, is this a date?’
“I hadn’t had one of them for four years and then Daniel O’Donnell. For the whole week we were together.
“My sister came out to Tenerife afterwards and I had a picture of Daniel. I told her I had met this fella and she said ‘Yeah go on’ and I showed her the picture of him and she roared laughing.
“She said ‘No, no you and Daniel, I don’t think so’. She couldn’t visualise it at all.
“He came out and we wrote and rang and I came home a couple of times. We were lucky it didn’t really get out for about a year. It was three years before we got married.”
She said she is now blissfully happy with her life with one Ireland’s biggest country star.
She said: “I am the person I am because of everything I went through. I don’t want to go through it again but I believe it’s made me a better person now and for that I’m very, very grateful.”
She said she loved making her recent album which included a duet with Cliff Richard but she is not thinking of getting into the music business.
She said: “It was a great experience to have done it. I’m not by any means looking for a career in music. I would not like to be going on the road and doing concerts. I’m terribly nervous.”