I Need Advice

So, I'm going to visit my girlfriend soon, who lives about a day away. I asked her out a really quiet long time ago now, and we've theoretically been together since. Our relationship is really shallow though. It feels like we're friends at best, and it's something I've been really struggling with more and more. In skype calls we don't say much to each other. Tonight we were playing minecraft, and one of my other friends joined the call. In a way I just can't seem to do, he suddenly had her talking and laughing. It made me feel kinda bad, like I was inferior. I've asked my gf about this sort of stuff before, and she said she wants to keep trying to make our relationship work but I just don't make her happy like other people can do. Is it really the right thing to keep investing myself in her, and trying to make things work? I have all these fears building up around our relationship, and I'm just not really sure what to do anymore.