It's a horrible feeling. Would you be able to go for a walk after work to get rid of the stress/adrenaline? Please don't let it put you off, as it's your body telling you it's struggling. Try warm baths, books, decaffeinated drinks, but keep with it. Also, try breathing in for 3 seconds, hold it 3 seconds, breathe out for 3 seconds and hold it again for 3.