I have had a severe headache for over 72hrs along with occasional nausea. could it be a side effect of my depo-provera shot? i got my 2nd shot on the 8th.

Most likely not: My guess is that you are having a migraine: a headache that usually is one-sided, severe, pounding pain with associated nausea, incapacity, and vision change. They usually start in the 20s. I don't suspect the Depo-Provera shot, especially since you first had it 3 months ago. Continue with your scheduled next injection, but talk to your fp about your headache and its details.