Spotting at 4W?

I am 4w 1d. I had extremely light peach tinted fluid (my fluids mixed with my husbands, sorry TMI) after having sex yesterday morning and then it stopped.

After a long walk yesterday evening, I started having very light brown and occasionally pink spotting that’s continued to today. No cramping.

As a side, my FRER was pretty dark this afternoon on a 2 hr hold. My vagina feels dry and closed.

Has anyone else experienced this? Should I be worried?