If you have been flossing regularly and effectively for a week and still your gums bleed then you need to do two things. Firstly, revise your technique as an incorrect technique can cause damage to the gums and this may be the cause of your ongoing problems. Secondly, speak to your dentist. If the problem is bad technique then your dentist will be able to advise you on this and correct your ways. Furthermore, bleeding could mean that you have a dental problem that needs fixing and a dentist will be able to eliminate this possibility. It could be as simple as needing a dental cleaning to remove an excessive build-up of plaque.