You are in fitday. It has a food log feature. You can measure and put in your food intake for a day. Do that for a few days (I know, people don't like to measure and count, but just three days is all you need...) and be scrupulous about it WHILE you do the induction for Atkins. Don't obsess. Just keep doing what you are doing and see the actual calorie count of what you are eating.
Look at what fitday says is your calorie baseline for your current weight and activity level ('sedentary' is the best bet to specify, because you don't want to overestimate your calorie burning). Then see what the calorie-in, calorie-out balance is telling you.
The reason I say this is because IF it is more difficult to lose with the medications you're on (meaning, they are contributing to the slow weight loss), at least your doctor will be able to see this. Don't write it down for him - actually log on to fitday right on a computer in his office and show him!
All the speculation about what medications do is just that. You didn't even mention what medications you are on and even if you did, that wouldn't tell anything definitive about your slow weight loss.
You can always just do the obvious - keep on with the Atkins induction and accept that weight loss is going to be slow and then maybe speed up and then slow down again and then speed up again. Low-carbing is a choice that people make and it works just like any other diet. It's not magic. As you can plainly see now that you're doing it for the second time!
If it's a diet you LIKE, then stick to it only because you like it. This particular thread in fitday has reports from people who have done Atkins before and lost weight. What this tells you is that they went off it and put the weight back on and now they are about to diet again and lose again. Maybe they will put it back on again and maybe not. It's like any other diet that way.
You have a doctor. Maybe you can have some sort of nutritional counseling from someone in his office. It may depend on how much weight you have to lose and how important it is to your health at your age, with your medical background. No one knows that background like you do and like your doctor does. Good luck, whatever you choose!