Lost friendship

She was a good friend, or should I say a very close friend. We have a lot of fun together in primary school, with three other friends of mine. However, when we reached secondary school, we grew more and more apart, she found some new friends, and got closer to them. I felt unhappy, but do not stop her from doing so. From that moment onwards, we started to become strangers to each other. Even if we are near each other, we wouldn't bother to say a "hi" to each other. How i hope that we could get back to primary school days when everything is so fun and relaxing, I miss the days we had together and i always will miss them.