How about this one. I have very mild asthma but in 2007 I was out lot from work from it. (Now in hind sight I am not sure if it was asthma and/or anxiety. Chest tightness, a symptom for both illnesses, was the main culprit.) My boss at the time had a sister's whose asthma was so bad she almost died from it. He started getting on my case for being out because of asthma. He even projected how many times I would be out for the year and that was "not acceptable."
Man (pun intended, :p), I was just like you with that job and the most recent one: I came home angry. I was never violent to my wife or anyone else, but I would get easily aggravated and maybe slam an inaminate object during the first 30-60 minutes I was home. She felt bad for me, especially if I told her if the day was crappy. We couldn't figure it until the waning days of my last gig.
Why wait til next year (even though it's over a month away)? Start looking into a business now. (Just a suggestion.) You're actually in a better position than me. You are working. Starting a business while already employed is better.