No period since January! What is going on?!

I am 20yrs old and have been on the same birth control pills since July last year and I had my period every month until this past January!. I continued taking my pills every month until 2 weeks ago at the end of a packet!. I havent had my period since January and I have taken a pregnancy test every month with results being negative!. I eat the same, sleep the same, stress the same, exercise the same (1-2 hrs a week) which is not much, and I took my pills everyday/same time each month!. When I went to my doctor and told her this a month ago she did not seem concerned!.!.!. had me take a pregnancy test -negative and said nothing else about it to me!.!.!.

I have had my period for 7 years without missing one so why now!?Www@Answer-Health@Com

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