changes delaying period

My period is usually very regular but this month it's a few days late so far. I'm 18 and not really sexually active; my boyfriend and I touch each other occasionally but no semen ever comes near my vagina. This month I've had a lot of changes, changes in sleep patterns, changes in diet, increase in excersizing, and a crazy amount of stress. I know these things can always delay a period but mostly I'm just concerned my mom will realize my period is a little late and think I'm pregnant though I'm certain I'm not. I've thought about going on the pill but my mom would freak out and take it the wrong way even though all I want is to know my period is on time. Any ideas of what I can do this month or months in the future to keep my period regular? Thank you!!