I wish I knew about the after effects after depo! I researched TTC after depo about 2 weeks before my shot would end (as me and OH had decided we wanted to try at that point), and heard some right horror stories! I was thinking to myself oh my goodness TTC is going to be put on hold until my periods even come back (and apparently that can take around 10 months).
However I was very lucky and 4 weeks after the shot ran out, I got a period! I'm now currently on my second AF since depo, and my cycle has been 33 days. 33 days is a little longer than my old cycles before BC, but I am hoping that they stay regular. I'm not sure if I'm ovulating though, but i'm staying positive.
Yes, there are some horrible things that depo can do to your cycle, but I think I was super lucky, as I only had one shot and lucky that we planned at that time otherwise I could of got another shot, not realising the long term effects, and suffered later on.
I'm sorry you're having such struggles, I've heard going onto the pill can help regulate your cycles, and quite a few women have had success from it, you could ask your doctor?
Good luck x