A bad day!

Today I feel very uncomfortable. I have a stomachache.

Today I've been feeling very uncomfortable because I have a stomachache.

(You can also say: "I feel sick")

This is so bad.

I feel so bad right now,

Better: "I don't feel good"

Torrow is the last day of the homework.

and my homework is due tomorrow

But now I haven`t finished.I`m worry about that.

But I haven't finished it yet. I'm so worried that I won't get it done,

Because I have no idea.

because I have no idea what I'm supposed to do on it.

Better: because I don't understand it; because I don't understand the instructions; because I don't understand the task.

Teacher kept urging me to hand in homework.

The teacher keeps telling me that I need to hand in my homework.

God knows how I don't want to write my homework.

God knows why I don't want to do my homework right now!