Cramping! 😒

I'm almost 18 weeks and have been having cramping seen last Saturday. No bleeding, and it's not majorly painful. Feels almost like menstrual cramping in my pelvic floor and sides. I'm also getting over a UTI that I was on an antibiotic for. I've let my nurse know about the cramping and they don't seem worried. I hate this! Anyone else having second trimester cramping? We heard her heartbeat last week and had a u/s two weeks ago and everything was fine.