Late due to stress?

I've had one of my most stressful months to date this past month. My period is slightly irregular and now I'm a few days late. I've been irritable, and I think I'm seeing signs ofy period. (Back/hips hurting) I've also not neen eating or drinking well, and I jad an awful case of strep this month, but I did have unprotected sex once, but he pulled out. Not safe I know. Should I be worried? Any experience with late periods, especially due to stress?