Help please!!!

Hey guys!! So I’m really just looking for some advice! I was on the depo shot for about 9 months it was the worst thing I could have done to myself honestly.... i gained about thirty pounds I broke out everywhere and my appetite was huge!! But the part I want advice about, I’ve been off the shot for 5 months now, and I didn’t get a period for the first maybe 4 and a half months. And I started getting these symptoms recently and I thought I was pregnant because I recently had un protected sex but yesterday I got my period for the first time since I got off the shot.... I’m wondering if anyone else has experienced this where they didn’t get it back until after they had unprotected sex? I know it sounds dumb but I feel like that’s the reason my period came back???