M.B.
Don't feel embarrassed about what is happening..... you do need to see a doctor and get some therapy, and maybe medication to help you through all of this.
You have been through some really tough times right now... the best thing is, you are realizing it, and know you need help. Asking for help ISN'T a sign of weakness..... it actually takes a lot of strength to ask for and accept help from others.
As you saw earlier, the Lexapro did help you through the PPD..... and you were able to go off it, but you do need it again (I know the doctor put you back on it). You really do need to go back and talk to him about this panic attack, and the fact that you haven't been able to go back to work.
Medication can help you through this... it is much better accepting the help that the medication can give, than becoming a prisoner to the feelings.