I Am 6 Days Late For My Periods. Last 5

I am 6 days late for my periods. Last 5 pregnancy tests showed negative but yesterday one test indicated faint positive. Consulted a gynec and she told me to take Norethisterone 5 mg tablets 3 times a day for 3 days and there are chances that I may get my period after 3 days from stopping the tablet. Is is the perfect solution. Help