I found it best to just eat what I fancied as it was better to have something in my stomach than nothing. I did rely on bread and cereal a lot but I found I drank a lot more water too which was good.
Once you start feeling better, then you can focus on healthy eating for you and baby. Just try not to worry about it too much at this stage. If everything turns your stomach you just have to eat little and often whatever you can face.
The sickness will eventually pass. It just feels like it'll never end at the time
If you can face fluids then drink lot of water, maybe try soups and smoothies to get you fruit and veg fix.
Remember to stay away from raw and uncooked eggs (no more runny yolks), pate, undercooked meats (so steak nees to be well done for now). If you google "what to eat in pregnancy" you should get a good list of foods to avoid.