Michelle....

The greatest thing about your post is that you recognize that you have a problem and that it seems like you are motivated to change that is more than half the battle. Irritability and isolation are common symptoms of depression. You really need to find a way to seek some help. I am sure that with one of your jobs you could work something out to get away for an appointment. Simply tell them it is a doctor's appointment(s). Do what ever you need to do to get the help you need (go to work early, stay late, etc.)., but just do it. You are far too young to feel so miserable, no one should have to suffer like that.