L.L.
yes,sounds familiar.My son who is now three went through this for about six months----but it seems to have started earlier for him....Some people had suggested car sickness/motion issue. I did the same things as you---I also found the portable DVD player helped.....I tried headphones with music and that helped too...Sometimes it worked and sometimes not. My son was the only one in my famiy that had this issue. I have three kids.. It was weird, He is ok now! I know how you feel though.