Hi and welcome,
Between your diagnosis with an HbA1c of 148, and your next HbA1c of 42, you seemed to have found a good eating plan. Have you strayed from that plan at all (other than an odd treat)? Did you relax and get a bit complacent? Is there any reason you can't go back to that plan? Do you keep a food diary including portion sizes and all ingredients? A food diary is an excellent idea, especially if you record your before and after levels alongside the food and look for patterns - increased portion sizes? Increased carbs? Analysing you current meals may help you find some of the reasons for your increased levels.