Welcome to 3FC!
I sometimes think that the hardest part of the journey is making peace with ourselves about our choices. Unfortunately it becomes that much harder when there's someone breathing down our necks about said choices.
One way to change negative thinking is positive action. Choose a goal. If you want to lose weight, choose a goal that will lead you in the direction of losing weight. As an example... replacing all sugary drinks with water. Or taking a 10 minute walk each day. For just one week make it your goal to do that one thing. Working towards a positive goal can help put us in a positive mindset.
As you achieve the goals you set for yourself each week, you'll feel more confident about setting more challenging goals and reaching them.
Start small & doable, make it a habit, build up.
You can do this! Can't wait to get to know you better on your journey