Had a 7 day period which was very heavy. normally my periods are 4 days, light and painless. i felt very fatige. could it be chemical pregnancy?

Take a test: If it were a chemical pregnancy then your urine pregnancy test would be positive. Take one and find out. If negative then you simply had a bad period this month. Consider birth control to regulate and present an unplanned pregnancy.

need to see your doc: You should see your gyn and have thorough exame and lab works then can tell you the real cause.