你必须照顾好自己英文是You must take care of yourself。
I'm sorry to hear that you are not feeling well now. If you take some medicine and go to see a doctor seriously, I think you should take good care of yourself.
Learning is very important, but your health is very important. You must pay attention to your health and don't lose your heart's excent. You are the best.
中文翻译:听说你现在身体不舒服,我很难过,吃点药和认真的话去看医生,我觉得你应该好好照顾自己,学习很重要,但是身体很重要,你一定要注意自己的健康,不要失去心的振奋,你是最好的。