Hi There! I'm on Day 1 of life without alcohol so please take that into consideration with anything I say...errr...write.
FWIW, I suffer from anxiety....have for years. I was put on Lexapro (10 MG) in 2004 and, although I have taken it every day, I never kept up with the original therapist that prescribed the medication. I also found out from my new psychiatrist today that alcohol actually kills any/all benefits from the Lexapro.
I'm not sure if you've ever been checked for anxiety disorders but, FWIW, you described a lot of my symptoms - shortness of breath, racing heart, tightness in chest. It can be really scary as a panic attack can mirror a heart attack and you definitely want to get checked out to make sure.
Anyways, the best thing I did was to get in therapy and to also get a psychiatric evaluation. If anxiety is playing any part with your symptoms, it is definitely manageable.
God Bless!
RacerX