period

last month i had a very heavy period that has never happened before it lasted probably 11 days, my doctor said my hormones might be imbalanced but i got blood work done and he said i was fine. this month i thought i was starting my period the same day from last month but it was very light, and there was some old blood but thats it. Has this happened to anyone else before? I’m a bit concerned because im not sexually active. could my cycle just be off track and might go back to normal?