IUD and no period??

Hi ladies! So I’ve been freaking out a bit for like two weeks now. A little backstory, I got my Skyla IUD in January, so I’ve had it over 6 months. I was sexually active before getting the IUD, but I got the IUD because my periods were so awful and heavy even with birth control pills.

So basically, I’ve always had a heavy period and have suspected endometriosis, but my gynecologist told me that they would only test for it if my IUD didn’t help.

Anyways, even while I was spotting the first few months, I still could distinguish when I was getting my period. It would be heavier and more consistent instead of one day heavy spotting and the next no spotting.

Well, they started out coming on time and being about 2 weeks long, not super heavy though. Then in May, I ended up being a few days late but when it came it was super heavy the first day and then hardly anything for 3-4 days after.

In June I was a few days late again but it was a little lighter.

In july I was 9 days late and it was mostly 8 days of spotting. I had maybe one or two blood clots that entire time.

Well now, I’m 12 days late and I had my regular PMS week, but no bleeding or spotting.

I really don’t think I’m pregnant since we used condoms they didn’t break. I know I should take a test, but I haven’t been able to pick one up yet since I’ve been working all day. Is it possible for someone with normally heavy periods to not have a period on the IUD?? I knew it was possible to stop periods if you had light ones before birth control, but is it also true for people who started out with heavier periods?

Thank you!