Did you recently update your version of R to 3.4.2 which came out last week? If so when you installed it, you may not have copied all of your packages over to the updated version.
Also, is the issue you're having only in loading the packages, such as through the library() command or using the pane in RStudio? Or are you unable to install new packages at all using the install.packages() command?
If it's the former issue, you can always try reinstalling the packages and try it again.