Spotting brown blood on Nuvaring

I have been on the Nuvaring for my first month, thought for a minute that I was pregnant because I didn't get my period when I was supposed to, took 2 tests both saying negative. My boyfriend looked it up and it said that you aren't supposed to get your period while it is in. So my doc told me to keep it in blood or no blood for the 3 weeks suggested. Then when I take it out my period should come. Well I am on my 3rd week of it and I skipped my period in November and now I am getting a heavy brown blood with really distrubing cramps and anxiety attacks. I wonder if the nuvaring causes these symptoms or that I might have endometriosis too.

I have been using Nuvaring on and off for about 4 years now. I just recenlty learned you can skip your period by putting a new ring in as soon as you take the old one out. I had no complications until this past month when I tried to skip a period for the first time. I had my ring in 3 weeks, and put another one in. About 2 weeks later I started spotting brown blood, and its been increasing and decreaing the past week and some change. I have read some girls say they change theirs every 4 weeks, which I am going to try with this current one because maybe I changed it too soon. I also used to be on the depo shot and spotted my entire first three months before stopping using the shot all together. This is just making me think that your body is not meant to skip a period. Somehow it needs to shed, and trying to control my bodies natural behavior will have its negative effects. Like I said, Im going to try the four week thing, but if I spot again Im just going back to the recommended usage with periods