super long period after several missed periods?

i'm 30 with hypothyroidism& pcos, my TSH was 22 in sept 2022, i was started on 75mcg and it went UP to 28, then raised to 100mcg and it went to 4.9, now i'm on 125mcg to optimise fertility, my periods havent been regular since i started it, ive only had one which was in jan this year and then i've had light spotting every week forthe last four weeks, now i'm having a period lasted longer than a week, could it be the length of time i havent had one they're just regulating and catching up? or could it be because the tablet is finally working and my periods are coming back? thanks guys!