Depo shot issues?? Please help

I don't want to go to the doctor ND they tell me Its completly normal. Ive been bleeding for 3 weeks now going on 4 it just came backheavy like the first week . I have some cramping not to bad and I feel queezy 9/10 in the am ... This is my second time with the shot but first shot since I started back on it. I started in February . The very first time I got on it I was fine no period untill it was time for me to get the shot .is it bc I've had my daughter so my body has changed ?