My last period is 10/2 and period every 30-35 days not so regular but usually fall into this period and I had unprotected sex on 10/31

I supposedly have my period very soon but my I see light blood
It is very light that it doesn't seems like its period
Last night it was reddish color and now it seems kind of brown

Can this be spotting blood or
Any sign of pregnancy?

It just never happen to me so I have no idea what it is

It could be spotting, which is a sign of pregnancy, but it may also just be spotting or your period getting ready to start.

You will have to just wait it out a few weeks and see if period comes or not.