Bloody mucus after nosebleed?

Whenever I have a nosebleed, I just put a tissue up to my nostril (not in it). Lately, when I pull the tissue away I pull out a glob of bloody mucus. It never happens anytime else (blood or no blood). Today I actually had to blow my nose several times for it to come out. I don't have a stuffy or runny nose, no allergies or cold, no sinus pressure. Why does it happen and where is it coming from?