Problem In Survival And Breaking Things

When I start a new world in Survival and the place where I spawn is very hard for me to survive, so I change to creative and look for another place for me to set up my home so I go to creative and when I have found a forest, I change back to survival and I hit a tree but I can't hit anything so I am helpless and I get killed by all the mobs. I hope you can look in to this problem and fix it as soon as possible.