Pregnant and heavy bleeding? Please read

I found out a week ago I’m pregnant. My tests got fainter and were negative yesterday. Last night they started getting darker and these are this morning. I had a large gush of blood this morning and it’s been light since. Has anyone had this and the pregnancy been okay? I’ve contacted early pregnancy unit they said to phone back in 3 weeks if my tests are still positive. I don’t understand why they dipped and raised again? My digital said not pregnant yesterday.