im 18 years old and ive been on the nuvaring for 5 months now and ive been on my period for 6 weeks now. it has been a steady flow but this last week i started to have cramps and ive never gotten cramps before along with lower back pains. i also have a bunch of tissue like stuff coming out with the dark red blood now. does anyone know what is going on or has this happened to them? ive had unprotects sex in the last 4 weeks but last week i went to planned parenthood and the pregnancy test came up negative. im so confused.