Getting sick a ton in Tokyo

Greetings. I moved to Tokyo back in December, and I really love my life here. But there is one problem, I get sick a lot. I get sick maybe once a month, so far I have had tonsillitis, a sinus infection, the stomach flu, a fever, and an infected eye. Has anyone else experienced this when moving to a large city in Japan or just a large city in general? This is my first time living in a big city, I spent most of my life in the suburbs of California. If this kind of thing is normal, or if any other people deal with this, please let me know. For context, I am a student at a Japanese language school and I teach part time. I really hate taking time off of work in school. I feel like ever since I moved here. My immune system has plummeted. Plus 診断書 is expensive.

by irelander2010