Well basically, me and my best friend are very close however since she returned from her holiday she has been very different and will hardly talk to me! She met a friend who apparently she became very close to and who she 'loves' (I presume as a friend as she has a boyfriend) But now I feel like rubbish and nothing compared to this lad, as she is extremely depressed that she won't see him again. How can I make us be the friends we were; knowing that I can't compare to how much she liked this boy and how much she's missing him

Talk it out with her. Get her to talk about him. At the end of it, let her know how you enjoy her friendship, and hoping that that doesn't change.

XenoSapien

She'll need time to sort out what happened. Stay in touch and try to continue to be supportive as I'm sure you've been in the past. Ask her to remain open with you.