Late period

Alicia • Moved half way across the country for the man I love and ready for the future
Okay so normally I'm not too concerned about my period being late because my cycle does what it wants most of the time. However, last night I had really strong cramps like I normally do when my period starts, but there was no blood. I did have unprotected sex a few weeks ago, but he didn't cum in me. Does this happen to anyone else or should I be worried?