I find that if I eat more than 70g protein per day, I stall. I also find that if I have things like cured meats, cheese, cream, and diet soda, it stalls my weight loss too. Eventually I will stop drinking diet soda but right now it is my crutch. I've seen people do zero carb for a couple days to about a week to break their plateau, but haven't tried it myself. I don't really pay attention to calories, I just eat when I'm hungry, and use a lot of fat. I try to shoot for 85% fat for the day, but a lot of times it ends up being 70%-80%. I've read that some people stall for 3 months. If you don't have any food sensitivites like I do, then stalls mean your body is repairing itself after losing some weight. Don't get discouraged though, just keep it high fat and try something different.

When did you see your doctor? Seems VERY odd that you could be in Keto for 6 months without losing weight--unless you are eating too many proteins? or fats? Maybe a medical review is in order?