I have damaged cartilage in my knee but I have no crutches?

Ok so my knee has been agony. I live in the UK and they said I have damaged cartilage. My symptoms are: -Slight swelling. -Pain when walking. -Bruising. -Clicking. There was nothing to make these symptoms occur but they have been like this for 2 weeks now. I went to A&E a week ago and I got a support bandage and told to visit my GP if I see no improvement. My mum says no whenever I ask for a GP appointment and its getting worse. I did a lot of walking yesterday so today my knee was clicking so I stayed off school. I think I might actually need crutches. I cant walk without agony. Bearing any weight on it is awful. What do I do?