K, it sounds like you are feeling more comfortable with the situation.
You've already received great advice from others, so I'll just step in with one comment from personal experience, related to Witz's suggestion to stay out of his head.
I have always found that, with HR, Policy, Difficult Bosses, etc. it's always best to stay just under the water line. In other words, don't do anything to attract a lot of attention to yourself. Figure out the corporate culture -- which policies are firm and which have a bit of wiggle room, what sort of behaviour is expected / appreciated / tolerated / unacceptable, what are the expected channels of communication -- through your boss, through HR or personnel, hallway conversations, etc. Especially while you're the "new kid", do a good job, but try not to obviously outshine insecure co-workers (your boss may also fall into this category), don't reveal a lot of personal details (especially about any health concerns, difficult child issues and the like that might mark you as "difficult"), and try to keep out of office politics. Once you all know each other a bit better you'll have a better sense as to what's safe vs. dangerous for your particular workplace.
I can hear such a positive note in your words. It's nice to see after the difficult times you've been going through.
Trinity