What to do if i have a lot of vaginal bleeding all of a sudden?

Vaginal bleeding: Sudden onset of vaginal bleeding: the best thing to do is to notify your obgyn immediately or go to the nearest ER if it is a lot. A lot would be soaking a medium to large size maxi pad in one hour and changing it every hour for the past 3 -4 hours. Go to nearest ER if you feel lightheaded, heart racing, chest pain, short of breath, faint or feel like fainting, profuse sweating and so forth.