Thanks for your query.
You should see a gynecologist immediately.
Such heavy bleeding with clots is not normal.
It could lead to anemia, infection etc.
The first possibility is a miscarriage
Other reasons are polycystic ovaries
and endometrial hyperplasia
leading to an abnormally heavy period.
Hormonal imbalance could cause build up of endometrial lining and then when it is shed off, it presents this way.
A biopsy should be done if pregnancy
is ruled out.