Pregnant?

So my period was due on the 1st of September it never showed, but I have pcos and my periods come every month on the same day except maybe 3 times a year it will be a few days late or early then we start on a few day every month. Anyways on the 7th of September I had horrible back pain on the left side for like 4 hours. It felt like it was grinding into my bones. That morning I had spotting. And it was only when I wiped after I peed and it was only that one time. Well its the 12th I took a test yesterday it was bfn.. could this just be a weird period?? I get having a weird period that's late bit never have I had one with horrible back pain for a day and spotting for a day or for that one wipe anyways. I thought af was coming... Also I've been going to bed early like around 730- 830 when I normally don't go until 11 and I take a nap during the day from 12 to 330 could my cycle been messed up and that was implementation or just not having a period this month... anyone else have this happen too them??