That's brilliant with the drinking....remember that it is a very slippery slope with an inevitable outcome. Sounds like things haven't progressed too far along the slope yet so that's great news. Your thought patterns appear to be the main issue. Try to forget all the what if's and when you catch yourself thinking this way try to do something to distract yourself. The thing you are describing is anxiety and your negative thoughts feed on themselves and tend to spiral out of control. This can lead to panic attacks which from my experience feel like your hearts racing with an accompanying very strong feeling of impending doom. There are some treatments such as using anxiolytics or anti- depressants but if you can do without then I would. Again, understanding the physiology of anxiety/panic attacks is a good way to learn how to deal with it. It is basically the body's "fight or flight" reflex being triggered without any actual threat being present.
Try to take your mind off things by keeping busy and your mind occupied and also learn relaxation techniques. Just take baby steps, give yourself a pat on the back for the 4 days, reward yourself, don't dwell on feelings like guilt, low self worth etc. No ! - Don't beat yourself up with all the "I should be's" - its the worst thing you can do, trust me.
You are a worthwhile human being, no less than ANYBODY else, value yourself, love yourself and keep re-enforcing these thoughts until eventually you will believe it and rid yourself of the negative thoughts. Think about how your wife is still with you, she must see the real you behind the curtain, think of the life ahead of you with your children. You have a wonderful life ahead of you once you get through this period. Sorry if I sound a bit preachy.....I'll leave you alone now. Look after yourself.....seriously, everything else will follow. Take care