My longest cycle I've had has been 41 days. I did have unprotected sex, but I tested 2 weeks after I had sex and it was negative. No indent, nothing. A week later (CD 37) and still no period. No spotting, no blood, just cramps off an on today in my lower stomach and lower back. What is going on? I know no one is a dr but if anyone could give me insight that would be great.

My periods usually stay around the 30-34 day mark.