I know it's not much consolation, but I hate New Year too - easily the most depressing night of the year.
Like you, I never enjoyed it much before I got ill, although I am wondering, now, exactly how long I've been ill, and how much this might have coloured things.
I've never felt very optimistic about the future, for a few years now, so I think, at some level, I sensed something was wrong, even though my concerns were very vague, and probably not anything I could have put my finger on.
I agree it's harder than ever to stay positive, now we know what's wrong, and that it doesn't get any better. But I think it's important still to try.
I think good times are still possible with MS - but that we don't hear so much about them on this forum, because it's human nature to post mainly when there's a problem, and not so much when good things happen.
I think also, sometimes people are reluctant to post the positives, in case it comes across as crowing, or insensitive. But I love to read if somebody went on holiday, or got a new job, or found a new romance, because it proves it doesn't have to be all doom and gloom all the time, and good stuff can still happen.
I am trying to look forward to Spring, and the better weather (when I generally feel better), and not to get too hung up on this gloomy time of year, when there's a lot of sentimentalising about the past.
I've got some nice food and nice wine in the house: I will NOT be starting 2012 on a diet! (That comes later. ;) )