h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

I don't understand why or how, but each time I try to really carefully put together the billing sheets for my hours and expenses for the month, I screw up.
I miss things, I get the numbers wrong. I put the right numbers in the wrong sheet, I send a sheet with old data and new file name. Also, one report format is for every day of the month, another is summary by month - but a second summary is by week, and when the month ends in mid-week, that throws me off. Travelling across month end also confuses me.
I try so hard, and I constantly fail.
I break down and have a panic attack - which helps like a bicycle for a fish.
Boss is upset, and calls and yells, and I freak out even more. I'm already crying because I fail, please stop being angry (is what I don't say, because I am ashamed).
I erase everything, and start over. I think I recognise every number, but I am probably wrong.
Again.
I don't trust what I do.
I hate month end.

Also, six or seven bills, for two different client companies- One for each project.
Keeping all those projects rolling. Switching, several times a day.
So afraid of mistakes, and of course it happens.

And tonight (or maybe tomorrow...) I'll have to do it again.
Wish me luck.