Laravel - VueJS Problems

I've been struggeling with Vue for the past 6 hours. The whole experience has been horrible, and It never goes seamlessly. I'm following Jeffreys tutorial on how to make a forum, and currently, I'm watching episode 36. I followed every step he took four times! Until 7:20 where he switches to the page and sees all the replies. The problem here is, I don't see anything at all. And for some weird reason, The Vue devtool tells me Vue isn't even detected on the page anymore but in the console "vue" tab it says it does. And I didn't do anything. He also made the post itself a Vue component, but that shows just fine...

I'm getting desperate to get vueJS working without any problems. It does not matter how many times I clear my cache or hard reload, The issues keep occurring The errors I get in my console is this:

Did anyone else have this sort of experience with VueJS? How can I fix this because it's driving me nuts! I'm not going to post all my files in this question just for the sake of keeping this post short, If they are needed, Please say so

Thanks in advance!

EDIT: I also keep getting an error when I run npm run watch. The error is this: