Plan B Effects orrr

Finished my period Oct 3rd. Took Plan B Oct 4. Withdrawal bleeding occurred 9-12 it was heavy like a period-but my period just ended. Fast forward today Oct 21st, ive had nothing but nausea, some cramps, fatigue, and now i feel like im catching some sort of cold. Could i be pregnant or side effects? Also i should note that i have endometriosis if thats anything. My period isnt due till Oct 28. Someone help!