I have been getting my period twice a month three different times in the past 6 months, is that normal? Is that a sign of premenapas?

Needs Evaluation. Cycles can vary however having two periods in a months time on several occasions is not normal and evaluation by your primary physician or ob/gyn is indicated here. There are many possible reasons that could be causing this and excessive bleeding can also put one at risk for anemia or low blood levels. It is better to seek attention from your doctor now as opposed to waiting until later.
It can be. When a woman is approaching menopause, her menstrual cycle length typically becomes shorter. This could lead to more frequent menstruation or irregular bleeding. A doctor can evaluate this to make sure everything is normal. Menstrual cycles can be longer/shorter heavier/scant.