PLEASE HELP! I don't know if I should go to the doctor or EMERGENCY ROOM?

I am feeling really nauseous, tired, dizzy, and shaky. One moment I will have a little bit of energy and when I get to move for a while I feel like I'm going to pass out from being so tired. I got strep throat this week and was really sick tuesday and wednesday. I only ate soup and applesauce on those days with juice or power-ade. I lost about five pounds from eating less. The last few days I've haven't eaten alot with my throat still bothering me slightly. Earlier today I wasn't responding well because I was so tired and started getting really shaky.. I ate candy, hard boiled egg, a banana and a little spaghetti pasta. It only temporarily made me feel better. Now I started to feel that way again just not as bad yet. I'm trying to drink orange juice to see if that will help. I had a popsicle earlier and it only helped a little but not alot. I am on antibiotics still. What should I do to stop feeling this way? I think I have low sugar from being sick but I don't know what to do to help it. I've never been like this before.