Looking for advice on following a diabetic diet in the US

I try to follow a diabetic diet, but I'm pretty new to the US (I'm from Europe), what ingredients should I look for in the stores? We have ALDI and Walmart mostly here. I would like to order sometimes uncooked meals with preselected ingredients, which provider is the best for this? When we are eating somewhere else, usually a gyro is a good option for me, but what meal can I order from pretty much anywhere, that's safe for me? (No rice, no potato, no sugar, overall low carb and good carb.) Is there a diet for hypothyroidism? I only follow the diabetic diet so far, but I need tips, we would like to conceive in this year later.