Feeling crap today

I guess it's a combination of lack of sleep and the poor air at work.
When I woke up this morning, I had a really sore head and everything was fuzzy. The thought alone of the heat and lack of oxygen in the office made me almost pass out so I called in sick.
After sleeping another four hours with a window open I feel a lot better.
I need to get a grip on myself and go back to regular, eight hour nights.
No plans for the weekend other than relax and tidying my place.