No Longer Feeling Hunger

For the past few months, I haven't been able to feel hunger very well. I only ever notice how hungry I am when I am eating, so I end up going one or two days without eating anything, but not noticing, quite often. This lack of nutrition leads to me feeling faint, but i still have plenty of energy.
Also, I throw up quite often and can only eat certain foods. Some foods, I can eat plenty of, such as fruits, vegetables, and certain meats. But other foods, i will throw up if i so much have one bite of them
The things i drink consist of mango juice, tap water, Milk, Tetley's Tea, and Starbucks frapps of varying flavor.
My stomach seems to be able to handle different things at different times, For example, I cant eat anything at all that inst a fruit for about 3 to 5 hours after waking up, I wake up feeling full, and not hungry at all. But always thirsty.
Unless its some subconscious thing, I am not aware of purposefully making myself purge, usually i will just be walking along, and I suddenly throw up. I never get bad stomach aches, just a constant full feeling. I am fourteen, Male. Can I get some advice?