Avoid trying to open do productive tasks for now. Try to set up morning rituals. One ritual per 30 days. For me it's meditation 30 mins in the morning. Your morning routine sets the structure and tonality for the rest of your day.

Look into if it fits your macro diet. It allows you to eat your junkfood while still dieting. It's not the best diet but it's a great start. As long as you hit your protein, carbs, and fats.

What you are going through is called rumination. It comes from thinking of the past or future. It creates emotional stress called distress. Research shows the best way to break rumination is through distraction such as meditation, being social, going outdoors etc. The distraction creates awareness which is one of the most important things in life.