What does it mean when you have shortness of breath followed by bradycardia but it only happens for a second.?

Its been going on for a while now, and its happening more frequently. Its like I can be laying down or just sitting down watching tv, and all of a sudden my heart rate feels like it slows down and I have to gasp for air but it only happens for a second. Then I am always tired and my memory isn't all that perfect. I have high blood pressure and my doctor had to switch my medicine out 3 times. I also noticed swelling in my feet and ankles but my blood pressure medicine also has a diuretic mixed in it. I don't know what to do. The medical director at my job has noticed my symptoms but he only sees elderly patients. Did I mention that I am only 21 years old!!!