I Am On Evra Birth Control Patch And Not Due

I am on evra birth control patch and not due to take it off until tomorrow and my period normally comes two days after but I feel like it's starting now, there is a tiny bit of brownish/reddish discharge. The last time I had sex was about 3 weeks ago but we were so careful and used condoms and washed hands and everything in between. I am stressing about this with a few days now and I feel like that could be a factor? Any help would be appreciated