Job situations like this are hard and people don’t necessarily make it better when they say “its just a job” (and I am not referring to any of the posts in this thread as of the time I write this, talking in general). The problem is we spend a lot of time each week at work, and despite being told it doesn’t matter, it isn’t who we are, to a certain extent it is, because unless you have some mindless job in a bureaucracy where you just exist, most people care about what they are doing and take pride in it.
I face something of a similar dilemma myself, there is a sea change at work and I am not sure which way it is going, if it is just a shift in how things are done or if it is shifting deliberately to make me redundant. For a lot of reasons, it would be hard to leave this job at the moment, with a kid still in college (and prob grad school), and with the finances I have, it is hard…and I am probably in your age range, which makes it complicated.
When dealing with a boss like that, it is hard, micromanaging and making decisions for you can make you feel like you don’t matter or have no input (I just had that happen to me, basically someone was hired for a position underneath myself that I had no right to veto it). It hits right at the core of what you are doing, and that really, really hurts. What I try to do (not always successfully) is realize that is on those who do this, that the micromanager likely is so unsure of himself as a manager that he has to do the work of his underlings to make sure it is done right. All you can do is suggest things, and if he chooses to do something else, try and accept the fact that you can’t change it. Try and take the attitude that if he gets in your face, or pushes over you, that it isn’t about yourself, it is about him.
The other thing I recommend (and yeah, this is the pot calling the kettle black, believe me) is to do what you can to make it easier at work by balancing it with your life outside. If your job is the kind of thing that dominates your life, you check e-mails at home, work at home, work late, try and cut back from that (hey, if the guy is going to make all the decisions, then why try and make his life easier?)…more importantly, try to find things in your life that affirm who you are. Maybe a volunteer activity where your skills or work will be appreciated, maybe in taking back a social life work took away from you, if you enrich the life outside your work, that can help (and keep in mind I am not offering this sage advice as some guru at this zen place, I am offering these as things I am trying to do [and not always succeeding!].
The other thing is try and see if there are other jobs out there, it can/will take time, but even the act of looking can give hope. It may not be easy, but given that hope it may make life easier for now. If you start looking now and working on it, you have the time to find something better that you like, rather than simply hanging your hat there.
I wish you well, I hope it works out for you.