Im confused/Birth control help 😢🤔😑😩🤦🏾‍♀️

I decided to get on the depo shot March 30th because i get really bad cramps cant get up to do anything because of the severe pain could barely eat anything because i would 🤢 puke or feel nausea etc.... all of april i was fine no period no cramps or anything as of may 7th I’ve been bleeding/spotting and im confused as to why this is happening because i was fine for the month of april didnt have any bleeding/spotting... I know this is a side effect but when i was on depo 3/4 yrs ago i never experienced this... are there different brands of depo? Because this time around I decided to get it somewhere other than the regular gyn that i go to