I'm two VERY different people professionally & personally. I've always walked a fine line there - for years I was a hardworking tax professional during the day & by night a social butterfly, bar-hopping 4 nights each week during RAH's performances, running with a very rock & roll crowd until the wee hours of the mornings. For years I kept both parts of my life very separated & only a select few ever saw that crossover. But that was a choice I made, splitting my life like that.
The feeling you are talking about sounds to me more like not being comfortable being yourself at work. Not liking the job or having passion for the work probably doesn't help, and it also sounds like your coworkers are just people you work with... not exactly friends. Not the kind of relationships where you would feel comfortable sharing about your recovery.
I honestly think it will get easier over time. In recovery I had to first work on rebuilding myself from the inside out & even though it was SO hard to identify all the "wrong" things about myself, fixing it all helped my self-confidence to soar. With that rise in self-esteem I also found it easier to draw boundaries with coworkers. My current job isn't my dream job by a LONG shot & my boss is so Super Codie that she is one of the biggest challenges to my recovery in a lot of ways. I also learn SO MUCH from this dynamic though, I get real-life experience putting the tools I learn in recovery to work.
But like the others, I agree that if the job is that bad it may never be a fit for you no matter how much recovery time you log. It may be best to keep looking for something that's a better fit for you.