Spotting in the middle of my cycle?

So yesterday morning I started spotting. It’s pretty light, and sorta pinkish/brownish. I’m not due to start my period for another two weeks. I was on Vienva (the pill) but this month my pharmacist switched me to Larissia (another pill) but I’m in the middle of a pack. I’ve been having sex, and we don’t use condoms but normally pull out, so I understand that pregnancy may be a possibility. Chances are, what’s going on?