So much pain...

I got my first depo shot in February of this year, and I haven't had a period since then. I've had 3 shots now, and right before I got my 3rd shot I had sex with my boyfriend a lot but it was all protected and he pulled out. I feel like SHIT for the past few days, headaches, queasy after I eat, my ribs, back, and legs hurt. I know these could be side effects of the shot, but I am just worried. Has anyone experienced something similar before?