Welcome on hcm.
Your story is suggestive of placenta previa
This is a serious problem of pregnancy
During whole gestation period you have to be cautious.
Now till delivery you should not do vaginal sex.
No sex with physical exertion.
You can have foreplay and after play.
You can go for oral sex
with no pressure on your body.
You should take bed rest
as far as possible till full term.
Get yourself checked immediately, by a gynecologist.
Good luck you need more.