Maybe try easing in to your program, smaller changes, so your body can adjust. Any chance you're adding in something you might be allergic to?
Have you talked to your dr. At all, some health plans have call in numbers, you can talk to a nurse or physician's assistant about your symptoms, maybe your prescription isn't quite right.
Do you monitor your BP when not "dieting" maybe this fluctuation is happening without the change in diet, then it would probably be related to your med.
Best to you