i'm so sorry to hear about your physical struggles as well as your emotional ones!! and with a baby who needs all your attention also! hang in there!!
if at all possible, do not go back to that work place. going to a stressful place is only going to make your physical illness worse and add stress that will eventually take it's toll on you and your relationships. if you need the income, try finding a part time job during a time of day that your husband can stay with your daughter. that way you won't be spending money on child care.
if you don't really need the money, but just need time for yourself, try finding other moms who need the same thing. you can take turns watching the kids while the other one goes out for some much needed you time.
it sounds like you really love spending time with your daughter. can you continue to just live off his income? i know it is hard sometimes but there are ways to cut costs and make it happen if it's what you really want. and i'm sure you would enjoy your time with her more if you weren't so stressed out about finding a job or returning to the one you hate so much.
i also became very ill after my son was born, and i am home with him almost all of the time. my husband occasionally will take him out for a walk lately and that is nice. i can take a bath or do something i need to do. he is a great guy, but he doesn't know when i need a break. i have to tell him. make sure you tell your husband when you need a break too.
i hope you can come to a happy solution! i will be praying for you.