Pregnancy with double sterilization

I know and understand that the chances of this happening are near impossible but I'm starting to get concerned. I had a tubal ligation almost 2 years ago and my husband got a vasectomy nearly 4 years ago. Every pregnancy we've had was on birth control and ended with severe complications which is why we chose sterilization. Well for a bit over a week now I have been having awful pains (somewhere between a pinch and stabbing) on my right pelvic area, along with nausea, skin breaking out, exhaustion, etc. If I was just having the symptoms I would write it off as a bug but my period the past month was short, about a fourth of its average time. Which is very unusual for me, before and after the tubal. Is it even worth me fretting about since there's only a .001% chance it could be a pregnancy? There's no STI involved either.