I really sympathise. I had mine from about implantation (I was sick every hour and a half for 24 hours, I thought I had the Noro Virus before I tested positive- lol!) through to about a week ago. I am now 15 weeks. Mine also, like parttimer79 is playing hide and seek. At about 13 1/2 weeks it started to be every other day. Then 2 days without, one day with. I was fine from last Thursday morning until midnight Saturday, and fine since (fingers crossed). I feel permanently hungover with it, like I have drunk about 2 bottles of a heavy red the night before.
I found the following things helped me ALOT - very diluted Ribena with very cold water- i get through about 4 litres a day, what with being sick I am so thirsty and plain water makes me throw up more oddly, satsumas - by the bucket load, orange ice lollys (the ones made with OJ you can buy), plain pasta - sometimes with plain tinned tomatoes with some herbs added and salt and pepper - I found I have to have the pasta really al dente, or slightly undercooked or I can't stomach it for some bizarre reason. When less sick and just hungry cornflakes with milk, salt and vinegar pringles. I found just eat a child size portion, even though after you are a starving, and have some more in an hour when you can, helped a bit. When I got over excited and had too much, inevitably I would be sick.
My sister, who is a doctor and has two of her own also recommend english muffins with marmite - she says the salt helps, and she went mad for plain pancakes, sometimes with lemon and sugar. Sorry if this is TMI but I basically eat anything when I could face it that I thought would not hurt too much if I saw it again - so I avoided things like crusty bread, muesli, anything sharp... Stick in there, it does get better, even if you find better ways to cope!