When I started year 12, I didn't say a single word, due to shyness. One of my teachers even said she thought I was mute.
Because my breaks were ridiculously long, I used to just take the tube home and play some bass guitar, so it wasn't that bad, although I do remember feeling really down for a few weeks. But I did make 1 friend after about 2 months, however he left after the first year cos he went to university and it was the same thing over again, but for an entire year.