Black discharge // Pregnancy? // unusual

I know it sounds stupid. Yet, I’m still overthinking.

Is it possible to become pregnant even though it’s only an outercourse? We did some dry humping without clothes on and I’m pretty sure that there’s pre-cum on it. I got my period four days later, and did a foreplay (fingering) on the fifth day of my period. About 16-17 days later, i got a thick black-brown discharge that lasted for four days and that is lighter than my usual period. I am now confused whether this is already my period for this month or just a discharge as it’s lighter than my usual period and it did not have a red blood. Yikes. I am so stressed out right now because of this. I need help.