Suggest Treatment For Spotting To Heavy Bleeding After Using BC Pill

hello my 18 year old girlfriend just started taking birth control last month its been 2 days away from a beeing a whole month now shes had spotting whisch is supposed to be normal but when she switched from the white poills to the green ones her bleeding got REALLY heavy to where shes wokin up with it on the bed shes had bad cramps, nausea, migranes, light headed, should she stop taking it now is it normal what should we do? thank you