Hi,
Firstly congratulations on being pregnant. About your head ache, it's probably because you are dehydrated, if you're being sick you're not keeping any fluids. So keep supping water, don't down any, I used a straw as it makes you sup little and often.
About eating, try not to think that you have to eat normally at the moment, if you feel sick, there isn't any point in eating a lot, so go for a little bit of whatever you fancy! Something plain like a jacket potato with a bit of butter or eat fruit. when you start keeping things down, your appetite will come back.
Don't forget to be taking your pregnancy supplements and not eating too late at night! Also try taking Gaviscon (safe in pregnancy) before you eat and then when you feel a little sick after. It may sttle you stomach before it has chance to feel sick!
Good luck and don't worry!