Weird period/bc questions

So 6 years ago I had very heavy cycles that were generally every 30-33 days. I bleed heavy for 5-7 days, clots, mild cramping, normal periods. I conceived twice with those types of periods. Nothing was wrong with me aside from low progesterone during pregnancy.

I then had an iud after my second child was born. The mirena. For the first few months I had light periods, which I knew could be a side affect. Then I stopped having periods. During this time I also went from 150 to 105. I had a very busy life and hardly found time to eat or sleep lol. Single mom life. About a year and a half into my mirena experience I started getting periods again. Well before and during my cycle I would bloat severely. I looked to be 5-6 months pregnant. Then one day my period was about a week late from when I normally came to expect it. I took a pregnancy test and it was positive. The next day I started bleeding pretty bad and went to the Doctors. I was told yes I had a positive test however via ultrasound I was not pregnant and that my ovaries were covered in cysts which was causing the bloat. They removed my iud because that was likely the source. I went back two months later for a recheck. Everything was 100% normal again.

At this time my period changed. It started getting shorter and shorter. It went from 30-33 days to 26-29 with a random off month of 24 or 25. My periods also started getting lighter and lighter going from a full 5-7 day bleed with a little spotting to 3 days with 2 days of light spotting. All my doctors say everything is fine. I’m normal I’m healthy. Just a little over weight at this point. So I lost some weight. Still a little overweight but not nearly as bad. But when my period began changing I was 105. (Underweight technically) but in the past 6 years I have gained almost 100 lbs and my period never went back to being heavy. Normally it’s dark red/brown the entire time. With a little bit of bright red blood on the second day.

Since I began eating better and losing weight my periods have stayed fairly the same. Last month I actually bled for 3 whole days where I could use a regular tampon and fill it in 3-4 hours versus it being half covered in blood at that point. Then spotted for two. This month my cycle was two days late from when I ovulated and general length of luteal phase. The blood is bright red and I have had loads of clots. I sit down to pee and clots come out. The morning I woke up and started my period I had several clots. I pull out my tampon and it’s covered in blood within two hours and has at least two small not big, clots.

My questions are did anyone experience this during their years of bleeding? Does anyone have a similar experience? Does bright red blood indicate anything could be wrong? Should I be concerned about the sudden extreme change? Could my mirena have rendered me infertile? Even if nothing is technically wrong with me?