Lost Contact With Bestfriend and IDK Why

Ihave a situation right now and it's been bothering me for weeks to the point where i just feel really heavy and upset when i think about it.

I've been bestfriends with this girl for at least a decade now and we are really close to the point like we are family. She moved to a different country three months ago and we would still communicate regularly despite the time difference. She promised me that we would always be friends and i feel anxious that she cut me off from her life without notice because our last conversation was at least two months ago and i've been thinking all sorts of reason why none of my messages seem to reach her anymore. I wonder if my replies are too boring or if i've done anything but last time i checked, we had no arguments and we would talk things over if we were upset. I feel anxious because she did something similar and broke off contact with some of her other friends for months without notice and im scared that she might have done the same to me despite the assurance that we would always try to keep the connection alive despite the distance.

To calm myself down, i'm just thinking that she's probably adjusting to her new life and needs time or is probably going through something right now. Maybe it is because of that, yet i still feel horrible almost everyday because she means the world to me and is like my sister. How can i stop being anxious and sad about it? How can i be more reasonable and/or move on?