Well, Proof, there are two ways in which you can address this problem.

1. When you're at work, try to be someone else. Let all their petty moaning flow around you, and silently mock them for their inadequacies. You do have to start at the bottom - it's a fact of life, but will make you a better person in the long run; ie, if you have cleaned the toilets, then one day, if you are ever someone's superior, you are perfectly within your right to ask them to do it - "I wouldn't make anyone do something that I was not prepared to do myself". Building site labourers are notoriously miserable fuckers - it's in the job description lol - throw it in their faces man - like, be overly cheerful and helpful, even when, deep inside, you wanna slap em, or summat - reverse psychology?
Dare your 'mate' to sack you - then sue em in court for wrongful dismissal lol

2. Get a different job - BEFORE you jack in this one - self preservation dude, a bitter pill to swallow, but like all meds, it'll be good for you lol.

As for the G/F... well, girls, eh?