When Should Ring Be Put Back After Taking It Out A Day Late?

I usually leave my ring in for 3 weeks! I am very good with taking it out on time. This time i was supposed to take it out on a thursday for my free ring week..I forgot to and I took it out Friday morning. When should I put a new ring in? And it is now tuesday and I am just seeing brown discharge. No period has arrived from what I see...Is that suppose to be my period? I am kind of worried what should i do? Should i put a new ring in this coming friday? HELP!!!!