Hi, my girlfriend and i have been having sex regularly with protection. She is a couple days late on her period. none of the condoms failed. I dont know if maybe it is irregular because she is stressed (which she has been very stressed lately) or if she is pregnant or maybe something else all together. I'm 16 so im kind of scared. I really don't know how she could be pregnant, i checked the condoms. None broke or showed any signs of wear, and we ALWAYS use protection. She also has not shown any early symptoms or anything.
Advice?

It would be helpful if i knew what could make a period late. Thanks.