i can't stop this...

why do i always feel this way,Its an on going feeling that never goes away.My heart skips beats and my breaths go short,I can't stand this feeling anymore.I don't know what to do.I'm worthless and affraid...or at least i feel that way.I can' live like this anymore..This ongoing sadness just keeps bringing me down.i'm never totally happy... not completely.i'm sad alot and i walk around with a fake smile on.i hide my feelings with fake facial emotions and lies about how i feel at the moment.I can't stand feeling this way much longer.Please help me figure out why i can't put a true smile on my face....And make it through the day with out a lie of my true feelings... ):