Your goals are promises to yourself. Something you want and are working to achieve.
When you doubt yourself, it tears apart your primary support. You can't get away from yourself and pretending things don't exist doesn't make them go away. You can't close your eyes to the obstacles you come across in life, but you can conquer them. Even though not everything will go as you plan.
You can't beat yourself up over things you have no control over. If you've made mistakes in the past, and everyone has at some point, then use them as learning experiences. You have to focus on the positives though. You know where you've been and where you want to be. You have to keep working to get there.
Sometimes we need a team mate or two - maybe more. There is nothing wrong with that. Just realize that they can't do it for you. They can only help here and there. Maybe their role is to teach you a new skill that you can use in your obstacle course.
Whatever happens, if you doubt yourself, you slow down - lose hope and focus - maybe even give up. If that happens then you have broken your promise to yourself. You can pick yourself back up though... even if you need a hand to get you there. It's still your choice to take that offered hand and rise.
If you want something enough, you can find a way.
"Necessity is the mother of invention" ~
famous quote with conflicting accreditation.
It's right, isn't it? Don't doubt yourself. Have faith in the skills you have. Your path is not the same as everyone else. It won't look the same. Things that work for others may not work for you, but that doesn't mean that you can't find a way to get there just the same.
Keep going. You CAN do this...
You've got this.