Nothing to wear except for black pants and flat shoes. Arrrgh.

Probably too late as well, but I've found a lateral move into different cultures can assist. Eg the Indian kurta is a stylish & forgiving garment. Never underestimate the power of basic black (Melbourne gal here!) and like @Primek says, a fabulous scarf/statement jewellery/cool glasses/hat/bag/boots/shoes can do a lot of fashion work for you. None of which is much use to you tonight. Forget about it now and see how you feel in the morning.