Sounds like time for a second opinion from a large medical center. You don't want to wait too long where a repair (instead of replacement) is not an option.
Since you live in Texas the Houston Heart Center in Houston has some of the best doctors in the nation. I know; I've had Open-Heart Surgery 3-times for aortic & mitral valve replacements.
It seems to me that you are having CHF (congestive heart failure) because your valve (which valve is bad?) is not working right therefore you have the pulmonary hypertension, fatigue, short of breath, etc.
I just got back from Houston because I was experiencing CHF. After all tests were done, my pulmonary hypertension when I went in was at 88mm!!! That is high! But after being there two weeks, the started giving me more lasix, 40 mg twice daily & adjusted all my other meds too; coumadin (blood thinner); aspirin daily, BP (blood pressure meds), etc. They ran more tests and the pulmonary pressure dropped to 38 mm. They still believe that the valve will eventually go out because it is 32 years old; I first had them implanted in 1975 when I was 24 years old. But for now, the meds are working & the CHF is at bay! Thank God!
You are still too young not to do something about your situation. Open-Heart Surgery & valve replacements are a frequent & very sucessful surgeries. Get yourself checked by a good facility. Good luck & let me know what happens. Take care.