Pregnant then not?

So last Wednesday I had numerous positive digital pregnancy tests. Had cramping from the start, did another test on Sunday still positive. Started bleeding heavily on Monday and still am today. Been to the hospital who did an internal scan and couldn't see anything. Checked bloods for hcg and they were negative. Feel so confused. They said it was possibly a chemical pregnancy and I was so early it's just gone. Is what I'm experiencing now a period or a miscarriage? Has anybody experienced this? How long should I wait to try again? I want to try straight after the bleeding stops.