Is my girlfriend pregnant or thyroid problem ?

I was just wondering if my gf could be pregnant or not. basically this month we have been fooling around like we always do the only thing different is that i started to finger her, but i made sure i always wash my hands really good before and after and she does the same thing. we have never had sex and i have never precum or cummed anywhere near her vagina. Her period is a couple of days late and i was wondering if she might be pregnant or not? she also has gained alot of weight recently and may have a thyroid problem since it runs in the family. She does say tho that she has beeen getting cramps lately. So is she pregnant or could it be a thyroid problem that causeing her period to be late.