Why Am I Having Blood Clots With Heavy Periods?

hi, im having some menstrual health inquires, im a 20 year old girl that has never really had an irregular period, but now im having one. i have seriously thick blood clotting that could fit in the palm of my hand, and my flow is very heavy. and last month i had an 11 day period and 2 days later i had a 4 day period, i dont know whats going on. im embarrassed to go and see a doctor.