Light blood during period on the 3rd day after have sex with pad, shorts and everything on. Am I pregnant?

I'm confused here - you had sex while wearing a pad, shorts and "everything"?

What are you asking?

How did you have sex fully dressed? How old are you?

If you actually had sex ( not sure you know what sex is from the way question asked) but if you had sex yes light bleeding is a sign of it sometimes.

You wait till time for your next period and if you miss it, you do a home pregnancy test