You stayed in, then saw the posts from the party. Ask honestly: do you wish you’d gone, or just wish you’d been asked?

Those are two separate wants, and scrolling confuses them in about ten seconds. One is about the evening itself, the music and the people and wanting to be there. The other is about being wanted, which has nothing to do with whether you would have enjoyed it. Most of the sting comes from the second wearing the clothes of the first.

Sort it before you decide anything. If you actually wanted the night, say yes next time rather than waiting to be persuaded. If you wanted the invitation, the fix is a real conversation with one person, not an evening with thirty.