Had the same thing happen to me, first time through a car wash and they swept right off. I'd suggest just ordering some replacements or trying to find some at a local junk yard.
I've noticed the same exact issue with my 06 2wd. Anytime I'm on a highway, it almost feels like I'm trying to drive through slick sand at 70mph+. Any little bump or gust of wind will make it drift.
