Very sorry to hear this amc.
As others have said, and I shall just add my two pen'orth too, please, please, please, GO TO THE POLICE. They won't be interested in you, they'll be interested in the lowlife scum who perpetrate shit like this. Rest assured, at least some of the group will have previous, for drug and violence offences. They'll preserve your anonymity and I hope you don't mind me saying this, but because of your disability they'll be more likely to act on dealing with useless scum like this.
Pieces of shit like this rely on people just letting it go, they will offend again.