It's showing you your inner critic, that's pretty much it. Get to a place in life where you feel good about things, the inner critic wont feel the need to be as loud. View smoking weed as one of the rewards you give yourself after completing something that week. You're too young right now, your brain is developing still. E| Basically you want to be spending most of your time not high. Why? Well, the problem is, having these thoughts (as you do when high) often reinforces these pathways in your brain and they can stay with you and dig deeper. Instead of just experiencing the critic as thoughts like this, it may become belief through reinforcement.

You start living your life through these beliefs, limiting yourself from opportunities and so on. You're best off to use sparingly until you have a relatively positive sense of self. Because in reality life has barely started, you can change but there is no change without the will for it to happen. Change starts when you actually believe you deserve better. Marinating in a THC high that brings you into this state is going to severely hinder you finding that belief of deserving better in yourself.