11 weeks Bleeding Scare..

I am 11wks today, We traveled over the weekend(3hr drive) with breaks in between. When we returned, i felt an urge to go use the restroom. As soon as i got my pants down i noticed bright red blood. We rushed to the ER where blood was drawn, pelvic check, and U/S was completed. Everything came back fine. My cervix is closed, my hcg beta are where they should be, the baby was active with a strong heartbeat of 177, no blood around or in uterus and no tears anywhere. While waiting, i bled again but since everthing came back fine. I was told to just followup with my obgyn. So I was given my rhogam shot, discharge and instructed to be on pelvic/ bed rest. The bleeding has since stop buy it still worries me. Has anyone gone through this? Where would the bleeding come from? I googled everything and nothing matches what took place.