I’m supposed to take my metformin at the exact same time every day.

Your pharmacist of doctor call give you an individual answer for you, and that is what you should go by. It depends partly on the individual, which is why you should ask them. But in general, my advice as a fellow patient on regular release metformin and not a medical professional is:
- For most medicines, you're trying to avoid double dosing. So in general, if it is past half-way to the time for the next dose, skip the dose you missed.
- For regular release metformin, taking it on an empty stomach causes diarrhea in many people. If this includes you, you'll probably find that if your meal is delayed by an hour or two, you'll want to delay the metformin you take with it. Or you can have a snack (1/2 sandwich, several crackers, banana, etc.).

The general advice for most people is to make sure you are taking the metformin with a meal or snack to avoid diarrhea. Try eating at similar times every day so that you're taking the metformin at similar times every day.

If you are starting off on metformin, on a starting dose, like 500 mg 1x daily, you have a quite a bit of leeway.

If you're on a high dose of 1250 mg spread over 3 meals a day, you've got less leeway, because you need to avoid double dosing.

I hope this helps. Remember, your doctor or pharmacist can give you customized advice specific to your situation and dosage.