Have just started a phd. I turned down another phd (one I was really keen on) in favour of this one, as I thought this one would be great. I get here and find there's a complete absence of what I was promised, am very unhappy (esp. as I turned down the other one).I want to quit this one and reapply for the other one: am worried that I've already turned it down once so would it affect my chances of being offered it again? What will my referees think/write about me quitting this one?