Self-sabotage

I have a problem with self-destructive/self-sabotaging behaviors that I seem to have no control over. For me this often comes in the form of usually doing something to hurt my job, with the final end result being ending up unemployed. I have seen this pattern unfold many times in the last 4 years, and have yet to find a way to stop it. In the past I have subconsciously, made myself physically sick where I was unable to work. With my current job I am seeing the pattern again, only this time instead of becoming physically sick, I am simply falling asleep at work, and I seem to have no way of truly keeping myself awake. If I ever get caught I will lose my job and I know this....I even fell asleep sitting at the table the other night. Right now I do work nights, but the self destructive behaviors come no matter what time of day I work, so that hasn't seemed to make a difference.

I know that I tend to do this around every 6 months or when I become extremely depressed. But the job thing happens about every 6 months and I am coming up soon on 6 months. :( I love this job and do not want to mess it up. Most people misunderstand and think that I do these things on purpose or that I am simply being lazy, but this is soooo not the case.