really heavy and I have been passing clots.

Hi,
Welcome to ehealthforum,
If you have not been sexually active, the heavy and prolonged periods could be due to hormonal derangements, thyroid abnormalities, endometrial hyperplasia, ovarian cysts, anemia, bleeding disorder, endometriosis, uterine fibroids, probable menopausal onset, etc. it is difficult to comment on the exact cause for your symptoms without examining you and going ahead with further evaluation. The exact cause can only be made out after careful evaluation and examination done by your doctor/gynecologist along with correlation with your symptoms and examination findings. Visit your doctor/gynecologist for further evaluation and assistance. Treatment as appropriate (based on examination findings and investigations results) would be started to help you control the symptoms and regulate periods. Consider being in regular monitoring and follow-up with your treating doctor/gynecologist and report any new/abnormal symptoms immediately. Drink plenty of water. Take adequate rest. Maintain healthy diet and lifestyle.
Take care.