Poop cramps?

So is this like a thing or just me? I’m 16w tomorrow and ever since around about 5 weeks I will get these AWFUL menstrual type cramps. The kind that hurt all the way around and in your sides. They don’t let up and aren’t intermittent- they’re exactly like period cramps. Every time I think, “On no this is it! I’m going to lose this baby!” Only to find myself having a bowel movement an hour or more later and POOF the cramping and pain are gone! Last night it got so bad it woke me from my sleep, no position of comfort helped, it was only my left side and it was heavy and consistent pain. I finally was able to get back to sleep and this morning I got up and had a bowel movement and all my cramping is gone. Anyone else have this??