How to tell if someone doesn't want to be friends anymore?

So my best friend and I have known each other for years and we're really close, but lately she's been ignoring me a lot. She posts a bunch of pictures online of her having parties and stuff that she invited pretty much everyone in our friend group to except for me, and kind of blows me off when I try to talk to her or text her. I know myself well enough to realize that yeah, I can be obnoxious at times, but she's the kind of person who's not afraid to tell me outright when she needs space. Up until now she'd always been a really good friend to me, so what's the deal? Is she trying to end our friendship or does she want o espaço or what?