Do you feel as if falling apart? Constant tiredness and headaches? Do you want to lie down and do nothing, just staring at the celling? It means that you "buzzed" as an overloaded computer...

In such a case you should do the folowing:
Take stimulators: tincture of Chinese magnolia-vine, ginseng, cordiamin; extract of green tea in pills. For raising your mind activity take a couple of pills of glycerin and a "good" dose of ascorbic acid (1-2g)every day during a week.
When forces leave you, sugar level in the blood is becoming lower, that's why don't think about your figure and eat a piece of cake or pastry.
Force your muscles to work. The best exercises to raise your work-activity is stretching your muscles...

You should be active, even if it's devilishly difficult for your state "out of spirits"...