4week prego. Went to hospital for bleeding but they didnt find whats causing the bleeding. I'm still bleeding but I have no pain or clots. Miscarriage?

Possible. At 4 weeks it's hard to tell what's going on. About 50% of pregnancies bleed early in 1st trimester and about 50% of those go on to be miscarriages. They may decide to draw blood tests several days in a row to see if the hormone levels are going up or down.