I'm in agreement with STASIS. I guess it's a case of "watch this space". You've messaged her and stuff, so it's up to her, now. Careful not to step into stalker territory, else she'll definitely not come back. Be all like...

"Hi, you there?"

"You there, yet?"

"So, I'm sat here twiddling my thumbs, wondering if you're there, ... are you?"

"Hello, again. I'm walking around your street, now, just thinking of you."

"Me, again. I'm sat outside your house, waiting for you to come out."

"Hi, I don't see you through your window, where are you?"

"Hi, I'm in your house, waiting for you to come home, so we can chat..."

LOL. Creeeeeepy. xD But yeah, ... just be patient, dude. Given you've known each other for such a long time, and seem to get along well, I'd say she'll come back. She's probably just got stuff going on. Granted, it would've been nice for her to tell you as such, but hey-ho.