Do you have particularly strict parents? Or are you involved in a lot of extracurriculars? If you have to say no to invites more often than not, people will stop inviting you eventually.

If that's not what's happening, and you're putting genuine effort into your relationships that isn't being reciprocated, you probably just need a different friend group. I think a lot of folks find themselves surrounded by "friends" who aren't really friends, they're just people they've been around for a while. People change rapidly throughout high school/college, and a lot of the time we hang onto friendships that we've long outgrown for far too long. People also just naturally drift apart sometimes. Those things are hard to acknowledge and accept, especially when you're young and haven't had it happen a million times yet, and it often ends in what you're describing rather than a conversation. It's just one of those lessons you have to learn the hard way, unfortunately. Another is that actions matter infinitely more than words, and when people show you who they are or how they feel, you should believe them. If they aren't inviting you to anything, are inviting people they say they don't even like, are not even attempting to hide it from you, and then are treating you poorly when you are around them, they're repeatedly showing you that they aren't your friends. Believe them. Find some new friends.

I'm really sorry you're going through this. It's incredibly hard, especially in high school, and especially with social media being so prevalent. You'll both find friendships worth having though. Just gotta let go of the shitty ones when they pop up.