Depo/spotting/pregnancy

When I got my first shot I was on my period and didnt stop spotting till I got my second shot. Got my 2nd shot on the 20th.

The last time we had sex was 2 weeks ago. Ive recently just started to have frequent urination, increased eating and thirst. Also been having crazy headaches. Is it even possible I could be pregnant when I just stopped spotting? Or could it just be the depo?