Which browser are you using and is it the same in any other browser.
What can sometimes help in IE is to go Tools - Internet options and under the Content tab, Clear SSL state.
Clearing the cache can also help for which you can use Disk Cleanup or the free version of CCleaner.
You may also want to consider changing the DNS servers in whichever adapter's Properties/TCP/IPv4 you are using, but those times don't look so bad, although I don't know what would be a reasonable time for Facebook - that could be down to their servers.