How can i start managing my diabetes?

Diabetes : Work with a good provider and stop most carbs, exercise, and lose weight.

Paleo diet/low carb: The best way to improve diabetes is by completely stopping high carb foods (grains, lentils, potatoes based items). Also avoid milk products. Contrary to popular belief, low carb food items such as eggs, meats, vegetables, avocados, saturated fat (butter, ghee, coconut oil), olive oil are very effective in normalizing blood sugars and reduce cholesterol. This diet may avoid the need for meds.

Fitness is key: My colleagues have given you good advice. You want to revise your ideas about eating and get back into that fitness-focused lifestyle you loved as as teenager. Find some people who are into some fitness activity that you enjoy and get with them; when they see you're trying, they'll befriend you and their mindset will become yours. Best wishes.