Late Period, HIGH stress?

Ok so now my girlfriend is 6days late on her period so we're starting to get pretty worried. We have never had sex and she is a virgin, however during intimate moments our genitals do touch and rub, however I've never ejaculated on her lower region. I did read somewhere else that it is possible to become impregnated from precum, and that it is possible to become impregnated even though the girls hymen is still intact. Also, about 9days ago (near when her period should have been) she went through ALOT of family problems, even ran away from home for a night due to the hostile environment. From reading more, I found periods can be delayed from high stress, which this would be a very high stress situation. We are going to try a pregnancy test in a couple days, but until then...whats your opinion, should I be worried? =/