health buffering

So I have had hyperinsulinemia (insulin resistance) and prediabetes for 4 years. I had a shock when I was diagnosed, the doctor said I was very sick. I walked out of the office feeling in shock and nauseated. I was truly not prepared or anticipated that diagnosis. It required changing my diet completely, removing all sugar, dairy and grains. I felt very confined in my eating habits since then. I have food intolerances and a leaky gut that I am constantly treating because of the sugar changes in my body. Early last year I started thinking I couldn’t carry on with that restrictive diet, constant meal prep, worry over what I was eating. I decided to see how my body would do on a more “normal” diet and my health became much much worse very rapidly. I felt out control and very fatigued. I gained 10 pounds in 8 months which is a lot for my body. I turned to sugar and carbs, my food intolerances grew and started to take over my life. I felt defeated, afraid for my future life-that I couldn’t keep up with my family. I started to think I couldn’t do anything about my situation when just years before I took massive action and did maintain for 4 years a lifestyle that gave me energy, maintained my diet to treat my conditions and felt really good and confident. I felt like I let myself down that I couldn’t seem to execute and be what I had already attained all those years before. I was eating my feelings.
My question is, How do I find my motivation and strength again? I live in “I can’t do it anymore” feelings and I know that I can do it! I have before and want to again. I feel like I am buffering against the thought that I cannot do it. Maybe a thought loop? I have never tried to break those, would really love some insight as to where to start or how to execute.