What is your definition of "priority"...?

It isn't healthy to drop everyone else when you find a new partner and make them your everything.

I don't think it's fair of you to say that she isn't making you a priority because she is maintaining friendships and going on trips with her friends. And why add in the bit about the trip being planned before you two got together? Do you expect her to not make plans with her friends now that you're with her? By saying the trip was planned before you came along makes it seem like you don't expect these friend activities to continue.

And just because she makes a comment about the new year starting off so great doesn't mean that everything else I her life is shytty, but your post makes it seem like you're feeling horrible because you expect to always be the best thing in her life.

I suggest therapy. I recommend CBT a lot. You're mind reading, making assumptions, and doing black and white thinking. I think CBT could really help you.