How to say these sentences in Japanese?

Question:

I am writing my penpal a few sentences in Japanese (we mainly talk in English). Can someone proofread my sentences?

I am trying to say:
OK, I will do my best!
Yes, my teacher is killing me XD However, he is a nice person. There is just a lot of homework.

Is it:
よし、がんばります。
先生は私を殺しています！XD　しかし、矢指の人です。たくさんの宿題があります…

Forgive my Japanese. It has been a while since I have written in Japanese.
Thank you for any help :)

Answer:

In Japanese, we don't use this expression "my teacher is killing me". It could literally mean murder or something.
By 矢指, did you mean やさしい? That kanji was wrong. Use either hiragana　やさしい or 優しい in kanji.

I would say:
よし、がんばろう
私の先生はとても厳しいんです。。。。　(T_T)
優しい人なんですけど。
ただ、宿題が多すぎるんですよ。

(T_T)
This emoticon means tears are running out of my eyes.