Confused. Help me please

*VENTING STARTS* So I have been ttc for a year now. This past year my periods have been irregular. Going from 28 days to 32-35 days. Kinda making it hard to catch when I ovulating. So in October I had my period on the 25th (Okaee cool) not even 16 days later I have another period November 14th (bummer right). Now if I go by the 28days before my next period it will be December 12th if not then than it will be December 16th. I took a test on the 12th just to see if I was pregnant and if was a negative. I had sex last night and afterwards I started cramping a little and been cramping all day. Why would that happen??? Is it normal ???? Or is it just because my period coming ???? I’m to the point now where I just want to give up and delete the app and call it a quicks. Maybe having a baby is not for me. Oh yeah my bf only have one ball could that be a reason ??? But then again he already have two kids 🤷🏽‍♀️ IDK 😐 *VENT OVER*