First of all, this is why we have insurance, for accidents. Don't worry about suing your friend just yet, it might not get to that point. The first thing to happen is that you will make a claim with the insurance company. Chances are your friend won't even be involved in that aspect. The only time we actually end up filing a suit is when we cannot resolve the claim through settlement. Most of the time we do resolve through settlement. Your friend will understand that you are hurt and need to make a claim. Don't beat yourself up over it.