How could native english speaker be miserable in China? You must be the most successful person, all doors are open for you! You don't even need to speak chinese to find a high payed job, so cheer up, man! You can do everything!
When I just came to China, I realized that my listening sucks, I didn't understand a word teachers said, it tooks one year to develop this skill, so be patient. And traveling around China is really help, because you have no choice, must to communicate with chinese all the time，it really improves your skills.