Has anyone had very close friend who suddenly started distancing from you?

My friend used to be really close, always calling or texting daily. Now, she rarely initiates contact, sometimes takes ages to reply, and doesn't send as many messages or reels. She's chatting with someone new on Instagram, which seems to be taking up her time. When she does reach out, it's mainly for favors, not just to chat like before. However, she doesn't seem to have any issues with me because when she does reply to my texts, she responds as usual, albeit after some delay. Sometimes out of the blue, when she's bored, she texts me saying she misses me and suggests we hang out. I'm confused about how to feel or what to do about this situation.