Unexplained spotting

I am 17w2d and have had intermittent brown spotting for the majority of my pregnancy so far. Thursday I passed a spot of bright red blood when I had a bowel movement.

After going in for an ultrasound (baby is good- heart rate 155) and having a pelvic exam to check my that my cervix is closed and long, my OB has not been able to find any issues. I am still spotting brown off and on.

Just wondering if anyone has experienced anything similar and gone in to have a healthy pregnancy? I know some women just spot without explanation. I’m on pelvic rest and she asked me not to do any exercise for now. Any positive experiences welcome!