I noticed streaks of blood in some mucus today when I had three BMS in a row. Can antibiotics cause this? I keep having BMS but they are hard, large lumps and some are maroon colored and looks like blood in them. My butt is sore because they hurt coming out and I've been straining a lot to get them out. I still have this urinary infection that won't go away. Now I'm not sure what it really is and the more I strain it feels like my bladder wants to drop out or something.