Caffeine? Bad or good? 5hr energy?

I'm 16 5"5 and anywhere from 108-115 pounds...my scale is messed up. anyways ive started drinking 5 hour energy. it makes me feel horrible, heart quickens and I feel so warm and then I get jittery. the plus is, I'm not hungry. I drink caffeine to replace food. is that bad? i don't even feel hungry...i just tried eating and I felt so sick. I want to eat but food just makes me feel gross. how can I be normal again? I like that ive lost weight but I don't think I have an eating disorder or anything.