My best friend coming back into my life isn’t what I thought it would be

My best friend and I were friends for 12 years of our lives and we were so close I felt like she was my sister. 4 years ago she went though a divorce and understandably it changed her. She went from laughing and joking with me on text and calling on the phone to eventually not communicating with me at all. I attempted to ask how she was doing for a while but eventually gave up. Fast forward a few months ago she adds me on Facebook and I accept. I send her a message on Facebook saying I miss her and asking for her phone number because she posted she lost all her corset information. That was in early October and she read it but never responded. I'm sad because I don't want to let her go but feel like I have to. Any advice on how to handle this and thanks for listening to my thoughts