The depo shot ruined me....

Miranda
I was on the depo birthcontrol shot for around 3 years. I finally went off of it about 4 years ago....I haven't had regular periods since and haven't been back on birthcontrol, regularly, and still I am not pregnant. My doctors say I should stay on the pill, to help regulate my period, but when I'm on the pill I get my period every other week and I either have it for a couple days or a couple weeks at a time. And it never comes when it's suppose to. Just whenever it wants to. Any advice for me? Should I stay on the pill and deal with my annoying periods? Or stay off it and hope for the best? I've been trying to conceive for years and nothing ever happens.