I'd agree with bonita123 - while I appreciate you haven't been on medication for the 20 years you've suffered from this for your personal reasons, I do think it's definitely something to consider. The best results come from a combination of medication, counselling/therapy and personal actions, so I'd recommend seeing a GP to start a course of medication (and counselling/therapy) soon! When I say personal actions, I mean a variety of things - exercise, nutrition, friends and family, fulfiling/meaningful charity or volunteering, meditation, goals etc. The most important thing is that if it was easy to recover from mental illness, services such as counselling and medication wouldn't be there. You don't have to go this alone - support is on hand in so many ways, if you want it (medication, counselling, therapy, Samaritans, MIND, 7 Cups of Tea etc)!.
When it comes to your past, I don't think it's something you overcome, but something you learn to accept has happened, and take forward. The aim is not to forget the past, but to find peace with it. Many times, there will be some things that have happened in the past that we blame ourselves for but seem unable to leave as resolved.
Speaking to others who have gone from severely mentally ill to recovered, they've all mentioned similar things that helped them. Some of the things I've mentioned earlier are key. But also, they mentioned that when things are really tough, taking note of the things that you care for the most, and using that as a marker of motivation. For many parents, it was their kids; for older people, it was their families; for some, it was their partner; for volunteers, it was duty to their charity. In this way, finding something to recover for can help - if you find it difficult to get better for getting better's sake, then focusing on getting better for someone/something can help!x
Much love <3