What Causes Persistent Bleeding Before Periods?

i am 48 years old and on yaz. i have been bleeding for the past 10 days and my period is supposed to start tomorrow according to my pill pack. the only thing i have changed is that i have been on a diet for the last 30 days and have lost 12.6 pounds and started to drink green tea 3 times a day. am i going into menopause or is it from the diet and green tea that i am having this bleeding?