Bleeding randomly

Just to put everything into context....

My period usually lasts between 3 - 5 days. I've had lower back pain for about a month now, but it feels more like a sciatica problem, I think. I have a boyfriend and we have sex with double protection (I've have a non hormonal IUD for 7 months and he wears condoms).

My last period started around 20 days ago and it lasted around 7-8 days, but I didn't think much of it.

Today I went to pee and realized I was spotting when I wiped. It honestly freaked me out because this has never happened to me before.

Maybe I'm worrying a bit too much but has anyone ever experienced this?

I googled my symptoms (which I shouldn't have because it always says something scary) and found out about PID. Maybe my IUD just scratched me or something? Idk I'm feeling uneasy about the situation and I just need some words of comfort I guess.