I've officially lost my mind dropping to 500 calories a day

I'm really tired of counting the calories of everything. Today, I only ate an apple and some yogurt, but I still feel guilty. I've honestly become afraid to step on the scale; it feels like even drinking water would make me gain weight. Is this situation normal, or am I exaggerating? I'm scared that my health will deteriorate, but I can't stop. What am I going to do?