I'm confused.

Okay so I have the nuvaring in and I've been using it since may obviously I change it every month like your supposed too. Well my dr told me I can skip my period if I don't want it anymore that it wouldn't be a problem and that's what I've been doing so I haven't had my period in 7 months but the past three days I've had a dark blood colored discharge like you get when your period ends. And then today it was more liquid like?? I'm just confused as to why this is happening. Any advice??