Hi there! I'm not far from London. You do definitely need a GP. That will help you access all the therapies and medication (if suitable) via the NHS.
I'm sorry your relationship has broken down, but I can guarantee that this is a bump in the road and you can and will get through this.
Sweetheart I'd hate to know that one of my family was suffering as you are right now, but didn't feel they could talk to me. I agree with Paula - you aren't a burden, you're poorly and need love and support.