Could you correct my small post ? Many thanks in advance for your help.

How are things? What's the weather like? I hope you and yours are in excellent health and in high spirits.
It is so chilly outside and the temperatures are is minus 11 degrees Celsius.
I woke up late today., had a meager breakfast of porridge and tea, and went to the shop to buy some food. The shops are full of people today and prices are so extortionately high.  Sorry for not writing but I had no opportunity to do it. I didn't have any internet in on my mobile as I ran out of my mobile internet. Secondly, I had no notebooks and it is so finicky [1] and annoying to type on a tablet PC.
Unfortunately, it's so cold in my room as the windows are threadbare and let cold air in. The heating is working badly poorly.
Take care.
Waiting for good news from you.

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[1] If you chose this word without the help of a computer or a thesaurus, I give you 50 points.  If you were able to spell this word without a computer or a dictionary, I award you a further 50 points!

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Great job!  Your letter is very close to natural English.