Im under a lot of constant stress and get emotional/cry sometimes. will it not make me get serious heart condition(if dont got one already), or develop a cancer(if dont got one already). and make my valve regurgitations go harmless to severe fast?

Do not try to fight your way through all this constant stress&emotional turmoil as inevitably physical symptoms will develop if you don't get help. . Your heart valves won't develop damage though. Your immune system can be weakened. Consult a mental health professional for stress management therapy and possible short term use of a tranquilizer.