The fact that you've had valve problems in the past is a red flag, and frankly, your doctor should have taked your concerns more seriously.
Demand to see a cardiologist. I had similar symptoms in my early 30's, and my PCP tried passing it off as acid reflux
and being overweight
. I knew it was more, and told him that I was NOT leaving his office until he referred me to a cardiolist. Less than 2 months later, I had open heart surgery to repair my valve.
For many people, myself included, the onset of heart failure
is the first clue that something is wrong.