Spotting before fertile window?Anyone else?🤔

Lily • Pregnant with baby #4

Today is supposed to be the first day on my fertile window and last night I noticed a tiny bit of brown spotting when I wiped, today after work I went to the bathroom and there was more brown spotting but on my underwear this time and when I wiped it was mixed with my cm but definitely more than yesterday. No fertile cm yet though...

Anyone else ever have this happen?