my dog has lost his confidence. :-(

Hello there
would like to get some views or experiences if anyone as had any.Georgy is very well behaved and loves other dogs,would always make a beeline for them,especially his friends he sees everyday and has never shown dominance.
when other dogs growl and snap at him he walks away.
Just recently he has been attacked,bullied by few dogs on seperate occasions but he cowers because hes scared & dosent want any agro.
Not sure if this is the reason but he will only walk so far now-he shakes,frets on the fields,parks that hes always known. he wont play with his friends he just wants to turn back and go home. we have to drag him-when he gets going he will walk but hes wary all the time and cant wait to go home.
At other peoples houses he loves it runs like mad in gardens,i suppose because he feel safe. We want to get our Happy George back that everyone knows. We are going to pet friendly cottages soon we go to every year so we are hoping he will get his confidence back.
hope to hear from you
tigsy xxxx