My best friend has all of a sudden decided that she doesn't like my boyfriend. We live together and she has told me that she doesn't want him over at the house and she has hurt her leg at new year so its not as if I can go over to his at weekends. What should I do because I do not want to make things awkward

Talk to her and ask her what's going on.

If something suddenly changed, you'll need to find out why.