Others have asked a lot of good questions -- without more information it's hard to tell what might be going on. But I do want to say that I don't think he needs to be eating or drinking in the middle of the night now (I'm not sure whether he is, but some others have said he is probably hungry). At 1 he should be able to make it through.
My younger son was also getting up (to nurse) during the night past the age of 1, and I was so exhausted, too. I decided I just had to do something because I was not functioning well at all. My husband and I chose one week that we knew would be difficult, but we decided I would not nurse him during the night anymore and that my husband would get up when my son cried, tell him it was time to go back to sleep, and then leave the room. My little guy is very stubborn, so he cried and cried, and my husband would keep going back in to tell him it was still time to go to bed (my son was in a crib in a room with his brother -- this wouldn't have worked if he was in the same room as us). After a day or two, it took less time for him to fall back asleep, and after the week was over he was sleeping through the night (and even started napping better!). I don't know whether you are still nursing, but because my son would just fixate on nursing if I went to him, my husband went. It sounds like that's not an option for you, but I think you could try this technique even if you are still nursing. If you aren't nursing, then your son isn't waking up for that, and you might just need to try waiting longer and longer periods before going in to comfort him (I'd go right in the first time he cries so he knows you are there for him, but after that let him try to get back to sleep on his own for a bit).
Anyway, it sounds like the key is to teach your son to sleep through the night somehow. I really think it should be possible at this age -- just be determined and persistant! I put off doing it for too long because, in the middle of the night when I just wanted to go back to sleep, it seemed easier not to do battle and to let my son have what he wanted. But things got so much better for everyone in our house once we got through that one rough week -- it was so worth it.