Everytime I eat something, I get sick. Help!?

Well, yesterday I got up and I had to run around in town with my mom. I didn't have time to eat anything. It's really hot here and I sat in the car without the air conditioner for like 20 minutes because I didn't feel like standing in line (my mom had to renew her tags). After that, I decided I should eat something. I don't eat a lot and I'm not a big fast food person but we went to McDonald's. I got the double cheese burger meal with a regular chocolate milkshake. Well I drank all that and I ate my fries then I got full. Well, the rest of the day I was in the heat. At walmart, I started to feel really dizzy and light headed. I had to lean on something to give me support. I was shaking and I felt like I was going to vomit. I went to the bathroom and washed my face and I felt some what better. I got home and drank like three classes of ginger ale and I didn't eat anything else all day. I didn't think much of it because I thought the heat was messing with me, plus the milkshake and fries are like really unhealthy lol. Today, I thought I should eat something since I barely did yesterday. I made myself a sandwich and got a pickle (I'm a pickle person). I started to eat the pickle and I felt like I was going to vomit. Just thinking of the taste of it right now makes me sick. I threw that away thinking it was bad or something and I started to eat the sandwich. Same thing happened. Can someone tell me what might be wrong?