Hello ! I'm a 36 year old female . Every time for the past few days when I urinate and then wipe I've noticed black granule type particles on the tissues n a some floating in the toilet . One fell into my hand as I was wiping n it's soft abt the size of grain of rice but brownish black colored. I'm not in any pain but I've been under a lot of stress and have missed my period for two months but I take monthly birth control pills . I've taking pregnancy test n had blood drawn to check pregnancy and all negative . I've felt a little pain here n there in my abdomen n lower back but nothing severe . I'm very concerned ! What could be going on?