Is it stress?

Lately I've been going through some stressful and frustrating times in life I had a really emotional argument with my mom over spring break last week my period was supposed to come this pass Monday and it is now Thursday making my period 4 days late. I have been cramping like I'm on my period tho but there's no flow. During this cycle I had sex for the first time in two months it was protected but I was wondering could this be the case too? Also I had an orgasm for the first time then too would that effect my cycle as well?