Friend stuff can hurt more than a bad grade, and people rarely say that out loud. There is a reason for it. Belonging is not a bonus during your teens — it is one of the things your brain is monitoring almost constantly. So being left out of a plan registers less like an inconvenience and more like an alarm.
Which means the first useful move is not strategy. It is admitting that this is a real thing to be upset about. People who tell you 'it's just drama' are usually trying to make you feel better, and it lands as 'your reaction is wrong.'
Then separate what happened from what you concluded. What happened: you were not in the photo. What you concluded: they are done with me. The first is a fact, the second is a theory — and theories get treated as facts fastest when you are already stressed. Write both down separately. It is surprisingly hard to keep panicking once the two are on different lines.
Next, decide which of three things this actually is, because they need different responses. A misunderstanding: someone assumed something wrong, and one honest conversation fixes it. A drift: nothing bad happened, you are just growing in different directions, and no conversation will undo that. Or a pattern of being treated badly: repeated exclusion, mocking, screenshots, people turning others against you. That last one is not drama; it is closer to bullying, and it deserves an adult.
If it is a misunderstanding, go direct and go private. Not the group chat, not a subtweet, not a friend passing a message. Something like: 'Hey — things have felt off between us and I would rather ask than guess. Did something happen?' Curious beats accusing, because accusing gives people something to defend instead of something to answer.
If it is a drift, the hard truth is that you cannot argue someone into wanting the friendship. What you can do is stop auditioning. Put your energy into one or two people who are easy to be around, including people outside that group. A friendship ending is genuinely a loss — you are allowed to be sad about it without turning it into evidence that you are hard to like.
And if you are being treated badly, keep it simple: keep receipts, stop responding, and tell an adult you trust. You should not be managing that alone, and needing help with it does not make you dramatic.