cheese on crackers are great, they fill you up and the cheese is good to help the nausea, you can also add a huge variety of other thins to it depending on what you're craving

, I did find I got sick of cheese and crackers after a while though lol.
Also snacking in general helps, eating every 2 hrs rather than waiting for meals so your tummy is never completely empty (ie eat before you're starvingly hungry).