Irregular Periods

I've been tested. No PCOS. My thyroid is normal, my hormone levels are normal and my uterus/ovaries are fine (ultrasound done).

I got my last depo shot March 2019, which means it wore off in June 2019. But I did take a Plan B pill in September of 2019, no Plan B's or BC after that.

My periods are still very irregular 35-41 day cycles.

Could it just be my birth control messing with my cycles? Or is there something else I should get tested for?