Dear Sally,
I'm sorry to hear that you're not feeling well.I think you should have a rest and rexa.You can listen to some light misic.Don't be stressed out.It's not healthy,and it's bad for your body to study too late in the night.You should sleep for eight hours every night.Why not see the traditional Chinese doctor and try some Chinese medicine?As for your Putonghua,you can get some conversation with your Chinese classmates,and your Putonghua will be better step by step.I hope everything will get better and better with you.
Yours,
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