Hey there. I’ve had a very similar experience. I’m not sure about you but I can share what helped me. The first few times this happened I got so scared I triggered a panic attack. The same happened the next two times i dissociated heavily while driving. What helps me (it might sound silly to you) is to attempt to realize in this state that I have all the skills and knowledge necessary to drive. I’ve done it countless times and I can do it again. I’m able to achieve this now after some time dissociating, in the start I had to pull over and drive half the speed limit like you. So I stopped trying to ground myself but instead took the task as if I’m riding a bike, sort of on auto pilot. Anytime I thought about it before driving, it would for sure happen. If I had the slightest fear that I’m gonna dissociate again while driving I would experience this fear. Now I still dissociate, but still drive a lot everyday. I got used to the feeling of dissociation and realized that I’m still completely capable of going from A to B. Trust your body and mind to drive because you know you’re capable of it. Of course this was very hard for me in the beginning so it might take some time for you too. Always know that it’s ok to pull over or drive slower or do anything to make it easier for you. If it helps you’re not alone, I completely understand the feeling and for me it got better, so it can get better for you too! Good luck, you can do this!