pregnancy or just weird period?

I had the iud for a little over a year and one day it just fell out. About 2-3 days later I got the nuva ring. I started my period the day after I put it in and I left it in for that. so move on two almost three weeks later I start having a lot of brown discharge to the point I had to wear pads. it wasn't like a period cause it was dark, that's never happened to me. I'm not supposed to start my period until the 22nd. I took a test but it was negative. when I got pregnant the first time I had a tiny bit of brown discharge caused from implantation bleeding. but this time it was a lot. does anyone know if it could just be a weird period from the change in birth control or should I wait till I'm supposed to actually start and take another test?