Rare Complications ?? Anyone

I’m 14 weeks pregnant. I had some dark brown spotting for a week and went in to have it checked out. The dr said it can be 1 of 3 things... whatever it is it’s covering my cervix on the inside but the placenta is off to the side...

1. It may be a blood clot that’s hopefully not attached to the placenta...

2. They also saw some bands that they think may be amniotic sac bands which the baby can get tangled in and possibly lose circulation to his limbs etc

3. It could be a blood vessel covering my cervix in which case would not be a good thing.

I have to see a specialist with a better ultrasound to hopefully get a more clear image and figure out what exactly is going on. I keep having sharp pains in my left side and am on bed rest for now. Has anyone ever experienced any of the three things the drs say it might be?? Sorry for the long post.