yeah it can be stressfull, i always worry about if i have everything i need. I have a checklist to run over in my head..... repeating "sleeping, food, alcomahole, tools for car" , easy. Make sure you have all that sorted and you're right. I guess people with nice cars don't need to worry about tools though.
and then you drive up the road on your way, get about 2kms away and think "sh!t, i forgot something", but usually, no matter what you forgot can be bought from a shop along the way if you really need it.
but also, we can all be so wound up by our normal work lives, that when you think about it, not much really matters, just go camping, try to relax, does not having done something really matter that much in life?