Should I go to the ER? Please help!

Got my second depo shot about a month ago, ever since then I've been having painful headaches everyday since and these past few days I've been bleeding, and my stomach is in so much PAIN. These feel stronger than regular period cramps. I didn't bleed the whole time I've been on depo, and now I am. It hurts so much and it won't stop! It feels like my stomach is twisting into a knot. I'm passing some pretty decent sized blood clots too. Is this normal? I feel TERRIBLE. It's been days and this keeps happening. Is this depo? Could it be a miscarriage? What is happening?! I feel like I'm dying!