Not sure if this is the same as you're describing, but I am very empathic and can often sense what someone else I'm in the room with is feeling. If, say, they're feeling anxious, then it's like I feed off that anxiety and start feeling more anxious myself (this is often an issue with my mother-in-law). Or if they're sad/depressed, then I might feel more sad around them.

I guess the same can happen if they're happy, that it can be infectious. I'm an introvert, but I sometimes feel a sort of "high" after a conversation with, say, a friend who is more upbeat and talkative. And I end up being more talkative with them than I normally would be. Yet too much of that "high" can be exhausting, too.