How much blood are we talking here? Like, entirely bloody puke, or puke with blood in it?
Personally, I often get nosebleeds on mornings after drinking. Often when I'm sleeping (such as this morning, only I haven't drank since Wednesday. I just get a lot of nosebleeds). So I'll have a lot of blood in my mucus for the first portion of my day.
But if it's definitely not coming from your nose it's probably not good. Maybe a stomach ulcer.