you maybe brushing your teeth too hard, try to carefully brush teeth in a proper technique. also try to replace your toothbrush with the one that has soft bristles. if your gums are sensitive, try to seek help from a dentist this can be another issue that you might not take for granted. have proper oral hygiene always.
persistent bleeding gums can be signs of gum disease or periodontal disease. this is high time that you consult a dentist. failure to treat this can make teeth start to fall out. do not forget to maintain practicing good oral hygiene like careful brushing and flossing.
be warned about the early stage of gum disease do not take this for granted for a host of health problems can be brought by gum disease. visit http://www.themouthdoctor.com for more tips about good gum care.

Get to the dentist. This could be serious. Or just get a new toothbrush, brush lighter, etc.