I was in your situation over 20 years ago and I remember it more clearly than any other time. The days go by slow.... and can be painful. I saw a LOT of guys just go UA or smoke pot or something to get out. Some seemed happy with their decision, a few not. The Navy made their lives as miserable as possible once they were caught. I didn't keep in touch with them so I don't know what they thought of their decision after time had passed.
I disagree with a couple other posters though. I won't argue with them; they are entitled to their opinion regarding an other-than-honorable discharge. First, you can get it changed to honorable after a certain period of time (6 months I think). But even if you don't, I have never been asked on an application whether I had an other-than-honorable discharge (which is what you would get). A few times I have been asked if I had a dis-honorable discharge; but even that was only a few times. It just isn't something that will come up much in your post-military life.
If I sound like I'm encouraging you to early-out, I'm not; just trying to explain it straight as I have seen it. Four years IS a long time though; don't let anyone tell you otherwise. You didn't mention how much longer you had. My last two years in felt like five. I can give you a little advice to make it more manageable:
Use your leave time; don't just sit on it and think you'll have a big cash out when your hitch is over. You have leave for a reason; your mental health. Use it and use it well; in one or two-week increments. That way you can get away two or three times a year. Plan fun stuff for yourself, both on leave and for the weekends when you don't have duty. Doesn't have to be expensive, but get away from the ship and from Navy people; the ship can be really depressing. Find some cheap transportation; a bike or a motorcycle. Or rent a car. Or borrow one from a shipmate. Whatever it takes; get out of there at every opportunity.
Start a journal and use it as a way to take everything out so your frustrations don't mount and cause you to develop an attitude towards others. When others look at you they should never see any frustration.
Work out; run or lift weights several times a week. This will be a good source of venting, and will make you feel better mentally and physically.
Put pictures of you doing fun stuff on your locker door; or pictures from magazines or the internet of stuff that you WANT to do.
Keep your friends close and your enemies closer. I mean that. If somebody is dogging on you and making your life hard; figure out a way so that they think you are their buddy. Never let them think that they are getting to you. Make a game of it in your own mind. Avoid them if you can, but if you can't then never let them know that they are affecting you. In your own mind you can be thinking all the trash you want, but don't utter one word of it to anyone.
Have sex.
Have a drink or two to settle your nerves, but don't waste your life getting smashed. It just drains your wallet and you spend too much time recovering.
Go get a massage. Don't tell your buddies though unless you want to be teased mercilessly.
Overall, try to live in the moment. Find something about your job that you like and focus on that while you are working. That is probably the toughest of all. Then, when your time is your own, make it your own and put the Navy completely out of your mind. Go fishing, or sunbathing, or women watching, boating, skiing; something that is NOT Navy.
Make plans for your post-Navy life. Not just generalizations either; try to plan out the next 5-10 years. The first two years should be planned in great detail; WHAT you are going to do and HOW you are going to do it. Identify the help you will need, the money it will cost, and where it will come from. Planning for the future will give you hope and help to keep a sunny disposition.
Good luck. I hope you stick it out; I think you'll feel better about yourself later in life if you do. I was miserable but I stuck it out. I do wish I would have taken more of my own advice however, and it would have been less painful.
