Is it possible to get pregnant 2 months PP?

My son just turned 9 weeks today. My partner and I had sex on the 22nd and the 24th, unprotected. I’ve been feeling light headed and very gassy. I thought I had just caught a stomach bug my daughter had earlier in the week.

This morning when I woke up I had a mucous like discharge tinted pinkish-brown. I am also on antibiotics (flagyl)