New Goals

I have many plans this year. I passed the test last month and I'll continue to take an important examination three months later. I have decided to go to the library to study every day. I plan to travel after the exam. I want to do more exercise, I've been sick last year and hate hospital very much! I need to eat more; it's weird that I look fat and strong, but I eat less all the time. I have to get rid of the bad habit of spending, I have no money even if I work. I might donate some clothes/clothing to the poor, I don't even wear some of these clothing/clothes. I want to change my bad temper, it's hard but I'll do my best. Now I'm going to make lunch, I wish hope you all have good luck in the new year!

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"three months later" means three months after the first exam (ie in March)

"in three months' time" means in three months from the time of you writing the entry (ie in April)

Just mentioning this as the first sentence could read better. Maybe something like:

"I passed the test last month, though I'm continuing to study because I have an important examination in three/two months' time."

You can't say 'these clothing' because clothing is an uncountable noun.