Depo, help!

Pajj
Well hey there!! I got birth control like 2 days ago. It's my first ever type of birth control, well except condoms but I mean the whole my body being the one taking it haha. Well, I did all the checks, I can't take the pill as my mother had blood clots, so it means I can't have it either. 
I then got my depo shot in my bum and boy it stung and hurt a little. 
Ever since I got this done, I've had cramping ever since, and I'm not sure if that's normal and I'm quite worried about it. It's just random cramps that do hurt a lot, but it always comes and go like a period kinda but worst. Also, sometimes like in the same day, I'll bleed a lot, then go toilet change pad and then the next change there's barely anything. 
Can someone with the depo tell me if this is normal. 
Thank you