What Causes A Light And Short Period After Being On NuvaRing?

hi I had a question about contraception. I am currently on the nuvaring and it has been going great with my periods being on time but this month I had a short light period for about 2 or 3 days and that was very odd for me because mine usually last about 7. I also have anxiety and stress so that could be it. Now this week is the week to take out my nuvaring for a week for my period but it's still august and I already had my period I think for that two or three day period. I'm just concerned what this could be about. Could you help me? Thank you.