You are constantly being undermined and berated by those around, the very people who meant to support you and lift you up.
You now find that you don’t want to do those things that you need to get where you need to be.
What you need to do is either tell those people how what they are doing is affecting you or they need to be removed from your life and invite people that have a positive outlook on life. That will support and uplift you, more than likely you have these people in lives and you have not been making use of them.
You need change that voice in your head, there is nothing wrong positive affirmations and keep telling yourself that you can do this and you got this. Another trick is to create positive habits and tasks that keep on track.
Also share your goals with those that will positive and keep you accountable for reaching them.