Committed Quitter

I’ve thought about losing the last ten pounds for a couple of years. I have tried to lose weight but I quit pretty easily. Now, after doing this work for two years, it’s like I’ve built more evidence that I can’t actually do this! So instead of starting I almost stop at the planning and have thoughts like “I can’t” or “that’s not enough” or “that won’t work”……and so, the cycle continues and I quit! It’s like I see the smallest defeat and then it becomes emphatically impossible. I am so quick to quit on things. Can you help me navigate this or provide resources for this dilemma?