I take 5 steps forward and 10 steps back :(

Yesterday night I felt so great, thought I had finally battled feeling nauseous but no, it's back.

So yesterday was Thanksgiving, and my famiy and I are on vacation to celebrate my birthday. My Dad wanted to go to a buffet because they were serving Thanksgiving food. I felt sick so much I thought I would have to go to the car, but I bared it and made myself eat. I felt a lot better after a pep talk from my wonderful mom and after eating something. (I put the nausea down to needing to eat) the rest of the day I was on such a high, i thought i had finally conquered this feeling because I literally made myself think about anything but nausea, emetophobia, illness, etc. I felt great, ate loads that night and slept well. Woke this morning, wasn't bad, but I kept getting lightheaded and dizzy (you know how sometimes you get up too quick and everything goes black fir a few seconds?) I had that a few times. We went out, I had slight nausea but did my best to ignore it. Then came lunch time. I was feeling quite nauseous at this point and again decided it was down to needing to eat. (sometimes at home i can eat, and 30 mins later feel sick to the point where I feel like i could throw up but I never do. Low blood sugar maybe?)
I have to eat something quick then i insantly feel better. I havent had it for a while though,
which is weird. We went to eat at a Pizza place and I ate. My dad wanted to go to the beach (and I'm sat right in the back of the car with no opening windows..) and gradually throughout the hour and a half drive feel worse. Then I have one if those huge waves if nausea and my stomach started cramping. As soon as I went to go to the bathroom the cramps subsided.
We walked on the beach, didn't feel great again, then realized I had acid reflux
because my throat and chest were burning. I couldn't take anything because I already had an hour or so prior. My brother let me sit in his seat on the way back (by an opening window) and I felt so much better, even watched a movie and decided it was all in my head again, plus I ate a meal. Then we went to a store, and I got bad again. I keep burping, and feel rotten, I keep thinking there is something wrong with me although all logic tells me I'm fine. Dont think it helps that 3 days ago I was outside lining for a ride behind a girl holding her stomach saying "she felt like she could throw up any minute" she looked anorexic, and she had loads of family around her who didn't seem bothered at all. Fair enough she may have been in one if the rides that I have heard make many people feel nauseous. Still, it's sticks in my mind, plus I think "what if I breathed in the air of someone who was sick and didn't know it?" I know this is almost impossible... :(

Sorry for my long rant, I just hate feeling nauseous more than anything and could use some advice...

I'm dreading going to Disney over the next fewcdays, and I hate that! I am in my favorite place in the world and feeling like crap! This should be such a special time for me and I don't want to remember it this way! I just feel like crying. It's my birthday on Tuesday, I want it to be perfect so much, my parents have gone to so much effort, my mom assures me everyday and I love her for it. I'm lucky to have her, she has fibromyalgia, hypoglycemia, acid reflux, and a few other things so she spends her life feeling nauseous. She is my rock and I don't know what I would do without her, I wish I was strong like she is...