Hello JR68 and welcome to the Discussion Board,
I'm sorry you are experiencing these symptoms. Unfortunately I do not know anything about your health ailments and I am not a medical professional. However, when you say you've been WFPB (which is great; congratulations!), are you completely oil-free and are you centering your meals or mini-meals around starch?
In people who have no health issues or maybe high blood pressure and/or cholesterol, feeling weak and shaky would most likely be attributed to not eating enough calories from starch. Vegetables and some fruit are wonderful! But since you can't consume too much food at any one time, I personally would eat probably about 6* mini-meals all centered around starch--potatoes, corn, whole grains (rice, quinoa, etc.), some beans/lentils, etc..
To this day if I don't eat enough starch and/or drink enough water, I can feel tired and even sometimes get headaches. Yeah, I should know this but sometimes I get so busy I don't have time to eat--bad, I know. So being prepared with cooked starches on hand is a key to this Plan...as well as making time for yourself to eat when you're hungry.
Wishing you the best and hoping your doctor will be more helpful! Ideally, if you could have a telehealth visit with a competent WFPB doctor that would be best.
Here is information on having a telehealth visit with a health professional with the McDougall Program. I do not know if
this would be financially feasible or if it would work since you are in the U.K. (it probably would), but you can check it out.
This article from Dr. McDougall could be very helpful to you in possibly finding a new physician.
*Counting calories and/or portions (with the exceptions of beans) is not recommend on The McDougall Plan. But you have to get enough calories in each day. Maybe 4 or maybe 8 starch-based mini-meals would work for you. Only you can completely figure that out. Using something like
this may help you get an idea of how many calories you are consuming to make sure your caloric needs are being made. Again, I cannot emphasis enough the need for starch.