If you are not against some help from technology, then there are software/apps that block internet access for social media web-sites etc e.g. freedom.to
You could also try browser extensions, e.g. for Firefox:
Mind the Time -- shows stats of internet usage;
LeechBlock NG -- blocks sites.
You could also try browser extensions, e.g. for Firefox: Mind the Time -- shows stats of internet usage; LeechBlock NG -- blocks sites.