It's completely normal. I just had my son four months ago and how well I remember being hungry all the time, not being able to eat enough, feeling sick after just a few bites of food. Ach! It drove me bonkers!
Load up your pantry and fridge with easy to eat, small, no-prep, healthy foods and eat them all day long. I finally figured this out after spending a few months feeling like I was starving but couldn't finish any meal because it would start making me sick. My poor husband had to make me three meals in a night sometimes. He became a master at small meals though!
Here are some suggestions:
whole wheat crackers
bell peppers with hummus
tortilla chips and bean dip
These were some of my absolute favorites while I was pregnant.
Keep some non-perishable snacks on your bedstand with your water and munch all night long.
Make sure you see a dentist while you're pregnant too... your dental health can dwindle when you're pregnant and affect your baby (weird, I know).
This phase will hopefully get better as you get further along, but remember that your body is at its most communicative phase in your life. If you are hungry for something specific, that food has something your body needs. If you cannot eat something specific, your body needs something else.
Try to find foods that you like to eat (at the moment) and eat all day long. Eat a lot of protein, iron, fruit, vegetables, whole wheats.
This is normal... annoying sometimes, but normal.