Is it normal to be worried about why my period is late than usual? for woman only

So after having sex in April I took plan b and I feel normal. However, my period won't come at all. And I know plan b have some side effects that I got from last time taking it like a week after taking the pill I got some spotting, and my period didn't come until 2 months later and the other time I took it it came a week later and no spotting. Also what I noticed is that this spotting only happen when we didn't use condoms. I don't feel anything unusual about me but I am stressing out about this and other general stuff + I've been exercising lately.
So woman what do you think is the reason for not coming?