short menstrual period - brown and spotty

I am on the NuvaRing birth control method. About three months ago I put the ring in late and so my cycle changed. Last month I had my period but the first day was light and it looked brown when I wiped/on the tampon. The next day there was very light spotting and it was red. After that it was basically over and there was nothing that came out on the tampon or anything. I figured it was because the month before I accidentally changed the cycle by forgetting to put the ring in back on time. But I currently have my period this month and it's the same thing again. Yesterday I got my period and it looked red at first but when I wiped and on the tampon it was brown. Then today it's very spotty and light red. What does this mean?