“Music reading…is very akin to word reading, with the added component of kinesthetic (bodily) response added on to symbol translation. Rapid word readers tend to read music rapidly and vice versa. Of recent years, studies in patterns of eye movements aimed at improving word reading speed have also suggested concepts which are adaptable to the problems of sight-reading at the piano.
It is now generally recognized that the visual techniques of successful sight-reading require: taking in as much notation as possible at each glance; constantly looking ahead to the next measure or staff; and keeping one’s gaze fixed on the score while seeing the keyboard peripherally (or by quickly lowering the eyes without dropping the head).”
– Ruth Friedberg (The Complete Pianist: Body, Mind, Synthesis)
Focus on the score not hands. Your hands should learn to find the positions for themselves. If not, you should train them to do so. Take a quick glance at your hands only if there is a big change in position, e.g. a big leap. Make sure your eyes can find their ways back to where you have left off.
Focus on the music flow but not your failure to continue. Do not waste time on feeling bad or blaming yourself being not able to keep your playing going. Do not go back to the beginning of a phrase just because you have made a tiny mistake such as playing one single note wrong at the end of the phrase. You can fix it when you practice, not when you are sight reading.
You are not important here, the music is.
More about sight-reading here:
Teaching Sight-Reading –
10 ways of improving your sight reading skills –