I hope your neck is ok!
My boyfriend has just got the clip on shoes. He hasn't ridden very much in his life and he thinks he is a professional. lol it does come at a cost though. He bought a new bike and was given shoes and everything. I told him over and over to practice in the driveway, just going up and down, slowing down, unclipping and stopping. But no, he 'knew' what he was doing. We went for our first ride together on our new bikes. About 1km down the road he went to put his foot down. lol it was quite an elegant fall and he stopped his bike getting hurt. He got back onto his bike after a quick check (and a little giggle from me), started off, and about 2 metres later, was back on the ground. He was very grumpy after that. After checking he was ok, we set off again. He still didn't listen to me about practicing, or loosening the clips.
We went for a 50km ride yesterday. All went well. I live on quite a large hill. We were about 2 houses away, and he managed to stack it again. He grazed his knee and was sad for the rest of the day.
It all happens. But I think you can prevent it by at least practicing for a bit. Its like going from a manual car to an auto, and just throwing your foot in for the clutch and its not there. I think you need to really just do it before thinking about it.
I'm getting my clip on shoes soon. So maybe we will be lying on the ground laughing at each other soon lol
Its all part of the experience, and adds to the stories, its just a pity it has to hurt so much!
Good luck with your pedals, don't give up