what to do about my best friend ?

me and this guy have known each other for 7 - 8 years now, we have been best mates for soo long, and i think we know each other more than anyone.

just before we started at different university's i rang him a few times (all of which went to voicemail) so i decided that i would stop being desperate for his attention and that he would see the missed calls at some point and try to contact me back... it has been a couple of months now and hes made no effort, to top it off i see Facebook posts between him and some other 'old' mates on Facebook, yet he has no time to contact his best friend ?! its as if hes completely forgotten me !

what should i do ?? i obviously don't want to be a needy friend and keep fighting for his attention, yet if i just let it go i feel like im going to lose the friend that ive put soo much effort into the last 8 years.

i understand that were both at different uni's now and have new mates, but that doesn't stop me from contacting other mates, even if its just the once to see how they are getting on !?