Paraskevidekatriaphobia

Maybe this is why I've had that Doomsday feeling all week...preparation for Friday the 13th!

paraskevidekatriaphobia (also friggatriskaidekaphobia) noun [U]the irrational fear of Friday the 13th
paraskevidekatriaphobic adjective, noun [C]
paraskevidekatriaphobe noun [C]‘Touch wood, cross your fingers, and pop that lucky rabbit’s foot in your pocket – and there will be an almost five-to-one chance that you will not then be troubled today with paraskevidekatriaphobia ­– fear of Friday the 13th.’(Tim Radford, The Guardian, Friday 13th June 2003)

No one is quite certain why people associate Friday the 13th with bad luck. Various theories have been put forward over the years, including Friday as the day of Christ’s crucifixion and the ancient Egyptian belief that the 13th stage of life is death. Whatever the roots of this irrational fear, it undoubtedly represents a very real concern to many people, so much so that a 1993 article in the British Medical Journal investigated the relation between ‘health, behaviour and superstition surrounding Friday the 13th in the United Kingdom’. The study reported the surprising finding that, despite the fact that fewer people chose to travel on Friday 13th, there were significantly more hospital admissions due to accidents than there were on ‘normal’ Fridays. Whether this is coincidence or not, the fact remains that many of us would confess some degree of anxiety about Friday the 13th, deliberately rejecting it as a day for significant life events like marriage or moving house.It is therefore not surprising that a term for referring to this fear, albeit rather unwieldy, has been coined in English. The noun derivative paraskevidekatriaphobe refers to someone who suffers from the condition, and paraskevidekatriaphobic can be used either as an adjective or as an alternative means of referring to a sufferer.
The term paraskevidekatriaphobia was first coined in the early nineties by Dr. Donald E. Dossey, an American psychotherapist specialising in phobias and stress management, who reputedly claimed that when someone was able to pronounce the word they were cured!