These Days

Recently, (These days) I have been feeling (am) really bad (,) because of my illness. (,...) The day before yesterday (yestersay ,) I had a high fever (,) and then threw (I throw) up several times around (in the) midnight. ( ....and) Yesterday,  I asked for leave from my work and stayed in bed the whole day, (,) just eating (eat) a few small (little) things. (....and) Today, my belly is very painful, so, I took (ate) some medicine (pills) and feel (fell) better now~how poor I am !~~~

In the title, you need to use initial capitals. For several days lately, you can just say 'recently'. In your article you did not have any full stops, so you need to punctuate and make separate sentences, instead of using commas. The comma needs to follow the last letter of a word (you shouldn't leave a gap). We would say 'around midnight' just means 'about 12 o'clock'. We would not say 'eat' but 'take'. I hope you have made a full recovery and are feeling better now! 

These days

These days I feel really bad because of my illness... the day before yesterday, I had a high fever and then I threw up several times at midnight....and yesterday I asked for leave from work and stayed in bed the whole day just eating little things....and today my belly hurts a lot...I took some pills and feel better now~how poor I feel ~~~