Intramural fibroids can cause problems in contraction of the uterus
leading to heavy mensturation.
In your case as the uterus is bulky I would also consider a possibility of adenomyosis
As you are unmarried presently surgery for fibroids is not advisable. Moreover these fibroids can cause problems in conceiving.
Medications cant dissolve fibroids.
Consult your gynecologist & ask your sonologist of the possibility of adenomyosis.