Yep, call your doctor. Pink, frothy sputum could be due to irritation/inflamation in the respiratory tract, but full bright red blood is an active bleed and needs attention. I know this sounds gross, but if you have a measuring cup handy, start coughing the blood into that so you can give your doctor an amount when you talk to him/her. When Andrew has bled we kept measuring cups in the bathroom, next to his bed, etc., so we always had an amount.