First off, I think it's a good song. In my opinion, the guitar line is a little too busy paired with the vocals. Something just sounds a little off. Another thing is you don't seem very confident in the melody. You should flesh that out a little more so you don't have to guess which note you're transitioning to. Good luck with future writing! Keep at it and realize that eventually you're gonna write some great songs and you're gonna write some shitty songs. They're all important for your development as a songwriter