Help a sister out and ease my mind

I’m 18 and not sexually active however I starting taking birth control 3 years ago due to heavy flow and horrible cramps. I was switched to the Nuvaring a little over a year ago and stopped using that this past august (I got surgery back in June and afterwards the Nuvaring wasn’t working anymore) after getting off of accutane which required birth control. It took my body sometime to get used to being off birth control, But my cycle was regular for the most part for several months and BAM! This past month I have had my period three times, i’ll have crampy ass periods for around 7 days, then 7 days free of period then it comes back!

When it first comes it will start out the first day or two with little blood, sometimes its even very dark brown which scares me, and then its so heavy that I literally will walk down the hallway and I will feel so much coming out and then my whole pad is soaked just from that movement.

Does anyone have any insight? Should I see a doctor? Should I be put on birth control again?