"Everyone is gonna feel that niggling feeling about coming back to routines, structures, and discipline; that is totally normal," explains Sizoo, director of international counselling centre Turning Point in Stockholm.
"But if you have a gut wrenching, sick feeling in your stomach, you really should think about whether you are going back to the right job."
Sizoo tells The Local that there is no normal amount of time for someone to get over their post-holiday blues - it could be two hours, two days, or two weeks.
"Just accept it, this is part of what it is to get back to your job on a Monday, but if you are still thinking 'I don't want to be here' in two months' time, then you should have a rethink."
But how? The first step, Sizoo says, is to accept your feelings, the second, to see what you can do about them.
"I am always a great believer in taking personal initiative. Don't wait for other people to feel like you do," she said. "Nothing ventured, nothing gained."
For more handy tips surviving the office grind, check out our top eight tips for readjusting to life in the office after Swedish summer holidays.