Кровотечение на раннем сроке: норма или тревожный знак?

Can someone give me some advice on early pregnancy bleeding. I have had two girls and i remember bleeding but it seems like its never ending. Im 4 weeks 3 days. But i have morning sickness, nipple changes. The bleeding calms down then comes back. I know everyones different and every pregnancy is but i rang hospital about it but they said its implantation but my minds still not at ease lol.