You do surprise me, as surely when you were first diganosed you would have been on the restricted carb regime or what was often termed carb exchanged regime, where you carbs per meal, snack where matched to your insulin intake!
If you are seeing your doctor I would asked to be put onto there carb counting course, if you'll lucky they will do the DAFNE course, or they may have one that they've created themselves (generally not quite as good as DAFNE)
As you need to know whether your background is set correctly to cover the day, then you can work out from what you are doing now, basically work out the carbs amount in your meal and divid by the injection you would normally have had... then work from there you will need to take a lot of BG readings at the right times, so that you can then worked out what is what etc