Oh no Jess
Had you checked the blind spot rather than just looking in the mirror?
I know only too well what its like to have someone hit you and its not your fault, and also have no witnesses
Luckily my accident wasnt in my car, and in the end it didnt go through insurance I just paid for the damage as it was a damn sight easier than fighting it, even though the loser was blatently in the wrong lane!
Hope its sorted soon!
The best thing to do is to get back out on the road again as soon as possible otherwise it will really affect your confidence