If you're ever in doubt, go and get checked, even if you're at the hospital every second day!
I had bleeding at 24 weeks and my scan showed a large clot behind my anterior placenta, my baby was delivered at 25 weeks (who is now a gorgeous almost 4 year old and doing fine!).
In my situation the worst-case scenario did happen, so it's not the norm and I hope I don't scare you! But it's a good reminder that if you feel something isn't right (even if you've been told to expect bleeding) e.g. excessive bleeding, cramping - go and get checked x