New to this app and I hope it works!

I haven't been "trying" to get pregnant but I have had sex during my fertile window a few months back to back but nothing happens. I might miss a period but test are always negative. I lost my first child in '10 and have been wanting a baby since then, just haven't been planning on making it a reality. I was on Depo for like a yr about 2 yrs ago and I haven't gotten pregnant not even once since then, and like I said I had sex during that window and nothing. I'm scared I might be infertile but I might need to give my body more time to "get right" but it still scares me when that thought pops up. Is it possible to become infertile after the depo shot? Or do I just need more time to adjust to having cycles cause I didn't have a period the whole time I was on depo.