Suggest Treatment For Regurgitation Of My Mitral Valve

I am 57 yrs old, not overweight, was in good physical condition except for a severe regurgitation of my mitral valve. I woke up in atrial fibrillation one morning & my surgeon suspected I had been in afib before so while he replaced my mitral valve with a new tissue valve he also gave me a mini maze procedure. This was Sept 2013. In my first echocardiogram my heart function was only 45% so they put me on carvedilol & lisinopril. Now I am lightheaded, my blood pressure drops when I stand up, out of breath easily, tired all the time, hard waking in the morning & frequent naps. I wonder if this is normal. I expected to feel better after the valve replacement but I feel much worse. I am considering stopping the drugs even though my doctor says I should keep taking them. I don t know what to do but it s interfering with my quality of life. I m planning on returning to work soon but can t imagine working all day. I rarely go 8 hrs without a nap or being extremely tired. My name is Kent Barber.