Back injury - I want to claim even though I signed the agreement.

Hello, I was the passanger of he car which caused the crash. I was badly injured on my back and I am disable (I needaa wheelchair now). The problem is that I am not ogyginaly form UK - ony my boyfriend who caused the accident is. As I trusted him I was signing all the documents which he asked me for.. I was stupid because I didn't try to translate it on my own and understand it.. He passed me the paper in which I signed that I am not going to claim any compensatio. I realised it only after one year when I started the claim procedure (he left me so I wanted my money back). I think that this agreement which he gave to be is unfair because I will never be able to walk again. Please, help me.