How do you know when you've gone too far?

Hi everyone, my first time posting here so any help would be greatly appreciated. My question is applying to dating, how do you know when you are talking too much, being ridiculous or that the guy is just over you?There is a guy I've been talking to for sometime now and we have been texting for a while. We planned to do something over holiday break and had set a date to meet. I'm getting kind of nervous though because a lot of our conversations have been becoming lackluster, in terms of his responses. At first there was a good amount of witty banter between us, now I can only get a lol or lmao. I'm completely okay if he isn't interested anymore, but for future reference I'd like to know.Thanks guys