It happens to people, at times, when they grow up & meet new people; you start to understand things the way they are. And eventually you realize that people you've known forever don't see the things the way you do, nor they try to see it or understand it. All you are left with is the option of keeping the beautiful memories and move on in life.
Sometimes you just have to remind yourself that it will all be okay, maybe not now, maybe not tomorrow, but one day. You will have to remind yourself of the fact that the things and people around you have changed and you are left with no option other than letting go and move on. Yes, its going to be a hard decision and you're gonna feel alone, lonely, in pain, hurt but just hold on to it for a while because that's what is good for you and who knows tomorrow might turn out to be the bestest day of your life?