I don't know what is happening to me. I keep getting these symptoms:

-frequent headaches and dizziness
-feel my heart beating... The thumping noise is horrible
-shortness of breath when I stand up and sometimes when i'm sitting
-faintness
-tiredness no matter how much I sleep
-i can't sleep after 2 hours I get in bed.. I feel tired, but I just can't sleep, and I tend to wake up for no apparent reason at least 3 times every night
-my hands and feet are always cold even if I feel warm

anyone know what's wrong with me, please help me... Any help is appreciated.