Good deal. That's what this particular forum is for, and I'm glad you utilized it.
When 'friends' do that, it's time to take inventory. Are they doing that, or are you seeing that based on your own perceptions of guilt or anger over being absent or messing up? Or have they grown and you haven't, or vice versa? At times, it's not so much that you've grown apart, but more that some haven't grown at all.