I had a big bleed at 13 weeks (like the first day of a heavy period). It was at night and i just panicked and went to A&E. They arranged for a scan the next day and everything was fine ("pregnancy" is 18 months old now!). Bleeding is very common in early pregnancy and everything is most likely fine but you need to get it checked out. Call the EPU- the number will be on your hand held notes.