I'm on the depo shot, and usually don't have any bleeding, I've had bad cramping before, but it's…

I'm on the depo shot, and usually don't have any bleeding, I've had bad cramping before, but it's usually at night, and goes away with medicine, today I've had harder bleeding, but not terrible, and cramping thay has made me lightheaded and nauseated, I took GasX and ibuprofen, and it dulled the pain, but it's still there, along with pressure like I need to push and still nauseated, I don't know what's wrong with me, has anyone else had this issue on the depo shot or in general?