Birth control!

Since this tab is supposed to be about birth control, I have a question about birth control! Lol! I went in to my obgyn yesterday to get the IUD inserted, turns out my cervix is tiny and way far up so it would be extremely painful!! So I opted out of that option, instead he gave me the 3 month shot, maybe and hour or two later I had cramps like period cramps. And I also felt a lot of discharge, I don't know if it's because of the lubricant he used for examination, or if it's me?! I just want to know the normal symptoms that come with the 3 month birth control shot.