You have 3 teenagers at home and a husband in delicate health.
I would say you may want to reach out to a therapist of some sort. That is alot of stress on you and a doctor may be able to help you as well as prescribe you something to manage the anxiety you must be experiencing with all of that going on. Even if it is someone to vent to and work through the daily stresses of life....it is a much safer option than continuing to drink.
I am sorry to hear that your husband is in that condition. It sounds like something he is powerless to control or fix at this point. You have the power to get yourself in a better place. Your kids will need to lean on you at some point and you want to be able to provide that support to them, don't you?