I'm not sure if this will help, but I figured I'd share my experience (plus, I'm bored). I had horrible OHSS with my twin pregnancy. I was in pretty much constant intense pain from conception until about week 15 . . . . I was continuously on Vicoden that whole time and went to the ER for pain 3 times! There was a time when the pain was so bad that I couldn't get up off the recliner sofa without help and peeing made me cry every time. I even made DH bring me a bed pan several times. I guess my point here is that it could be WAY worse for you!

That's not to belittle the difficulties you're having, of course.
I was lucky (??) enough not to have very bad m/s. I did, however, have almost no appetite for the first 12 weeks or so. I think I only gained 7lbs in my first trimester. I more than made up for it later, though, gaining 65lbs in total. I agree with what others have said about just eating what you can eat and not worrying too much about nutrition. There will be time for that when the m/s goes away (hopefully). Personally, I couldn't even take my vitamins most days because my gag reflex was so bad.
I was able to eat more starting at about week 16. I drank a lot of Boost and Ensure to get calories and nutrition. I also drank a lot of Gatorade to stay hydrated. It's kind of funny--I ate extremely healthfully before getting pregnant and then when I was pregnant, I ate like a picky 10-year-old. I don't think I ate veggies more than twice during the entire pregnancy. I got a fair amount of nausea again during my 3rd trimester and the only thing I could eat some days was Cheetos! One day I ate an entire bag myself! Isn't that horrible? I joke that my babies are made of Gatorade, Mac & Cheese, and Cheetos!