The following steps will help.
1. Get a good nights rest. If you are sleepy, you are finished!
2. Avoid all forms of dairy products, instead have a non greasy dry toast for breakfast. Toasted bread is best.
3. Use Bova Compounding seasickness tablets. They are quite good, although any seasickness tablet will knock you around a bit, and make you drowsy. Bova compounding are found in Caringbah. Bova has ginger and caffeine in them. Ginger to assist your stomach to stop churning, and caff to wake slow down the affects of the tab making you sleepy, although I have complained to Bova that they do not have enough caffeine in them.
4. Take plenty of food, drinks and snacks with you. I found being on the chew all days helps a great deal as well. I usually take a heap of smoked salmon sandwiches with me. Plenty of salty crackers or nuts, plenty of nectarines, apples and a couple of chocolate bars.
5. If you have a juicer, try and juice ginger and have it watered down with something you enjoy drinking. It helps settle your stomach. I usually take a few bottles of V with me and will have them when I start getting drowsy, as all tabs do this to you. Ginger beer is also good if you cant or wont juice fresh ginger,
6. Drink plenty of water and remain hydrated.
7. Do not overdose on tabs, this will also make you more sick. I find having something in your stomach assists with settling your stomach.
I would pay a years salary to have this problem corrected. Its a fishos curse, but hope this helps