Haven’t had period in 4mos not pregnant)

19yo Female. First day of last full period was February 24th (125 days ago). Periods are normally ≈8 days of fairly light-medium flow. Had 3 days of extremely light spotting April 22-24 (inc. pink discharge) didn’t even need to wear a liner or tampon.

I do have an IUD which had to be replaced two years ago because the first one Immediately starting coming out after being placed. The first one while I had it (8 mos), shortened and lightened my periods gradually and they had stopped after a few months. As mentioned before I have had this IUD for two years now and until now, i’ve had mostly regular periods.

About 3 years ago, before having my first IUD placed, my GYN said I may have PCOS due to my irregular periods, but never officially diagnosed.

Only recent changes have been a change in my sleep schedule and due to that I have been eating a little later in the day and fewer meals.

I am not pregnant, took a test tonight which was negative.

Since it has been over 4 months, should I start being concerned or did my periods just randomly decide to stop due to IUD after 2 years of regular periods?