Hi Billijay,
First don't worry too much, it's always hard, it sounds like you have early signs that the doctor is acting on. Fortunately we can live very well with some reduced kidney function but it is important to slow any progression down (when you think of it people who lose a kidney manage well and that is a 50% loss!)
I've just looked back on your previous post. It seems that you have done really well losing lots of weight and getting down to normal levels. So really well done on that. That's the first step already done.
As to the ACE inhibitor, actually it's fairly normal practice to put people on these if they are spilling small amounts of protein (microalbminuria) as it can prevent or slow progression.
In fact it's relatively common practice for many people with diabetes to take it a small dose as a preventative medicine even when they haven't shown any protein in their urine (I do). They also have been found to offer some protections against strokes and CVD .
You vaguely mention problems, and as your earlier post mentions asthma, I wonder If the ACE inhibitor is making you cough (a well known side effect) If so, do go back . There are several different versions and even a slightly different class of drug called an ARB which is said to be less likely to cause a cough .
Beyond glucose control and weight this article from the specialist unit at Edinburgh suggests that
it's important not to smoke ( I doubt you do that with asthma)
That cholesterol is kept low and BP is kept fairly low
"Controlling blood fat and cholesterol levels helps prevent heart disease and possibly strokes, and may slow the progression of diabetic kidney disease. The current data points towards a target total cholesterol of <3.5mmol/l if you have microalbuminuria."
The recommended target blood pressure is
125/75mmHg in diabetic patients however, the lower the blood pressure the lower the risk of problems"
http://www.edren.org/pages/edreninfo/diabetic-kidney-disease.php