Hello LHay! First of all, welcome to the forum and into Duromine family! You should keep in mind that weight is not always the best indicator of “fat loss”. Measuring your waist, breast, thighs, neck, and so on are another great way to see if your body is “shrinking”.
As to your question about exercising… since you have various health issues, no one but your doctor can give a truly sane advice.
Duromine can provide you with some extra energy that people usually use to make themselves used to increased physical activity. If you get tired quickly, try at least dong the plank exercises. These work miracles. You can’t take long walks, right? Means you need something to act quickly. I would suggest short Tabata sessions, or HIIT 5-7 minute workouts, which you can find plenty on youtube. On the other hand, I am not sure if you are allowed to do these and how they can affect your overall health condition. You can help your body develop stamina by exercising regularly and slightly increasing the intensity/duration. (still, I am not sure if you are allowed to do this).
If you want to make sure you eat enough, try writing down and counting the caloric value of foods you consume for a couple of days. Make sure you also get all important substances.
As for increasing to 30 mg. I am sure your doc will check your BP and heart rate and will take the decision that suit you better. I know that 15 mg is quite effective for many people, while others don’t feel anything at all and switch to 30 mg. Remember, your health is the most important thing. Best of luck and hope you will keep us posted on your progress