Why this code is slowing down

Hello.

Iv made this little code, its in difficulty a bit higher than my skill (copy pasted most of it, but i know what is what)

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It makes first row in around 5 secs, second row in 10-20 secs, third takes long, never allowed it make 4th run.

Allready tested option to stop macro and let excel rest for couple secs, same delay.
Comments changed to english, fixed minor bug
Made some more experiments - starting from different row returns same incrasing delay (doesnt matter where is first one)
While "on breake" excel is running smoothly.


Some explanation to macro:
Its some sort of calendar, days in columns, actions to be taken in rows. Cells inside filled with "1" (first picture should be inserted) or "0" (second one).