Hit a car while reversing in parking lot, now Im sued

Hi. I received a statement of claim for 2M. Other driver said he is suffered insomia, fear of being in vehicle, etc.. the accident happened in parking lot when i was backing up to a parking spot and the other car was going in my direction and I hit his car. His car has minimal damage. Anyone experienced the same? Is it better to get own lawyer or just leave insurance lawyer to deal with it? Will this cost me too much? Please help I’m stressed.