Am I selfish for not wanting to hang out with a friend's plus one?

Am I selfish for not wanting to hang out with a friend (let’s say, J) now that they added a plus one? It’s winter break so people are coming back from uni for a bit, and I was excited when J reached out saying they were back and would love to hang out! We started making plans, and while making plans, I got super busy. While I was super busy, J asked me if it would be okay if someone joined along. I wasn’t able to respond until the next day because of work, and I replied ehhh about the plus one coming along since I hadn’t really hung out with J one-on-one in a long time. They then responded that the plus one had already agreed to hang out before I responded, and that they would be coming along. I used to be good friends with this plus one, but now they don’t talk to me or check up on me, and whenever I do so to them, they rarely respond. Now I feel like I’m being selfish about being upset that this plus one is being forced into the plans, and I’m thinking of canceling plans with J due to this (to clarify, J is not making me feel selfish in any way). The only caveat of me canceling plans with J would mean I wouldn’t be able to see J while they’re back from uni, and that would mean I’d likely have to wait another 5 months to hang out with anyone, whether it be J or anyone else. I’ve only hung out with old friends twice over the past 4 months and my mental health is starting to take a toll due to how little I get to see others and hang out with them. Any advice? Am I being selfish? What can I do?