Could I be going through menopause at age 27?

I know it sounds weird but before my period was always on time just like clock work give or take a day or two at most. now within the last 4 months it has been crazy and I have been 9, 11, 12 days late and now i am 15 days late this month. within the last 3 months i have unexpectedly gained 30 pounds very quickly with no change in my eating habit's and i workout 3-5 days a week. I am always feeling hot. there has not been a change in my stress level except for stress about weight gain. I started having periods at 9 and half years. Since i started having periods at a early age could i also be going through menopause at such a early age? I am NOT pregnant. I have taken multiple test over the last couple of months and they are all negative. My doctor did not seem too concerned so should i be concerned or get a second opinion?