my period

So I'm 3 days late. I wouldn't really think I'm pregnant and I always use condoms and he pulls out just before. But I'm curious to know what's pushing it back. I've started exercising more and in that last 2 weeks I've been to the gym or fitness classes about 4 times. I never used to work out before this so could this be pushing it back. Or the fact I've broke out bad and I've been pretty upset about it, but I wouldn't say stressed? What do you think?