Thoughts? Help?

Noele

So i had missed my period for about a week, on monday i thought i saw a positive pregnany test (very faint line). Went to the doctor that same day came back negative on their end. Could’ve been too early but my friend was convinced that i was pregnant. I went to work the next day (tuesday) and started bleeding a bit. Went to the doctors once again to check what was going on. They did and ultrasound and blood work, not pregnant. So Wednesday i was bleeding like i normally do on my period with clots, big ones. Thursday was bleeding no clots, ended the night with hardly any blood. Now today im not bleeding at all. My period usually last me about a week or more. Not 3-4 days. Anyone know what could possibly be going on? Miscarriage? Late period going fast? Please im very worried and a bit scared