Not sure it was wholly the OP's fault that he ended up at that school, nor do I recall him saying he was warned before hand. However he should have researched the setting to see if it was to his liking.

When I came here a 10 years back I had those exact same problems, both from the food, and the extremely polluted air. I was sick non stop for my first 6 months here, it was a total nightmare. It was only after purchasing antibiotics and taking them for 1 month solid that I got better. Try being sick for 6 months, not fun. At intermittent times after that I had to again imbibe in antibiotics, it took some time for my system to adapt, I guess I am sensitive. My first year here was physically horrible.

China has many different things you will need to adapt to, like I said, sometimes environmental shock, which includes shock to your system in the form of illness, can be worse than any culture shock. Regardless I stuck it out and am today just fine, and am not bothered by the bad air or the food. I did however lose 11 pounds my first 2 months here, that's all I'll say on that.

I disagree about the food, I love Chinese food, always have, and find it superior to western food, all a matter of opinion and personal taste I guess. OP be brave, and don't focus on the negative. Try to find things to do, spend time online researching and learning new things, use your time constructively. Even where you are there is much more to do then was available to people even 100 years ago, let alone 200 or 300 years in the past. Those people survived and thrived. Learn from their example, you might find you thrive with less distractions. Or maybe not, only time, and you, will tell.