Проверьте пожалуйста текст на английском! Для IELTS

Я немножко все переписал, в меру моего понимания вашего текста (я не уверен, что правильно вас понял на 100%) - поработал над грамматикой и общей стилистикой. Если надо, могу пояснить отдельные моменты.

Dear Jack,
I'm glad to hear from you again! As you know, i changed my job last week and i want to explain why.
Firstly, the working conditions were absolutely slave-like - I had to work double time, imagine that! I was really exhausted every day after work, and that's why i didn't write you. Secondly, i was shocked by the fact that my workplace was in the basement! Gosh, it was horrible! But an old friend of mine convinced me to change my job and invited me to his company.
Now i'm working in a new carpenter's shop, where i have everything i need at my disposal, for instance, modern tools and stuff. We are given a 15-minute break every 2 hours, when one can have a free coffee or a tea. As a matter of fact, i have a good salary and so I can afford a long trip to Hawaii.
Oh, and i didn't tell you! Me and Mary are planning on getting married next month and i want to invite you to the wedding!

Write back soon,
Your friend George.

I- always a capital letter; I wanted to explain; Mary and I; write to me; punctuation!

I was glad to hear from you again!