I feel like am losing my best friend, how can I get them back?

I have been friends with my best friend for more than 12 years. Just recently we have drifted apart, because we have started our “grown up lives.” She moved in with her boyfriend, and works, goes to school etc, so do exept for the moving in the boyfriend part. I stilllive with my family. These last months it she has not make the effort to make time for us to hang out. It ‘s me making the effort to make arrangements for us to hang out with fruitless results. I feel in a away we don’t share similar things in common anymore like we did. I don’t have a large circle of friend, neither does she. How can I get my best friend back? Maybe she needs space to adjust to her new lifestyle ? But she has forgotten about me for several months now. The last time I saw her was because I went to her house.