I'm 2 weeks late for my depo shot (Which I am not going on again.), and it was my first and only shot.

But since then I've been getting a lot of weird symptoms.. My nipples are VERY tender (only the nipples!), I have on and off spotting (spotting for a couple days at a time, repeat up until today.) I have nausea but not to the point of vomitting, I get occasionally dizzy and I am having a lot of anxiety!

I've read that these are also side effects of the Depo shot, but they are also pregnancy symptoms, which can be very confusing and scary.

But also I've taken 2 HPT and they were both negative, my expected period is supposed to be today as well, I think, I might be thinking the spotting as a period..

I keep telling myself I'm not pregnant and my body is just catching up on missed time! (:p) BUT it's no help, I also only have had sex once since the shot wore off and it was with protection.

I guess what I'm looking for is what is the possibility that I'm pregnant here? Am I driving myself crazy? I just can't get over the sore breasts and nausea, I've never experienced this before. I should mention I only had sex once unprotected during the time I was on depo.
Would the HPT come out positive if I already had these symptoms too?