If you're using SLT Fibre connection, or ADSL/broadband connections, likely that Facebook will not load at all across Sri Lanka.
As officially being told on Twitter, the Telecommunications Regulatory Commission of Sri Lanka has ordered Dialog (and possible other telcos) to restrain 3G/4G services in and around Kandy.
Independent of this, problems accessing Facebook over SLT net connections appear to be spread islandwide.
Easiest & safest way around the blocking, at present, is to download the Opera browser (http://www.opera.com) and use its built in VPN (http://www.opera.com/computer/features/free-vpn).
Or if you already have a VPN, by using it.
