It sounds like you have a pretty good sense of what you want and don't want at this point in the relationship, which is great. Just to echo Sam, it's completely fine if kissing isn't a thing you enjoy or even want to do.
I'm glad you like seeing your girlfriend happy - that's a mark of a good partner! You also deserve to be happy and comfortable, too. Since you mentioned it feels a bit icky and it's starting to get you down, this sounds like it might be a good time to talk to your girlfriend about how you feel about kissing and other kinds of intimacy (by the way, here is a big list of alllll the kinds of things you might be interested in doing
with your girlfriend, all across the intimacy spectrum.)
How would you feel about starting a conversation with your girlfriend about how kissing makes you feel, and also what other kinds of intimacy you do enjoy with her? You'd probably want to emphasize that it's not kissing HER that the issue, but just the act itself, and that you really love X and Y with her. How does that sound?