I have found that the weight loss comes in fits and starts. It's not linear.
This will sound odd, but it may help you to eat a little more calories. You need enough calories that you have the energy for exercise.
The effortless weight loss zone may be way more effective for you for weight loss than the super low carb zone. If you want to do a once in a while super low carb, the best way is to not eat at all for something like 14-18 hours. In other words, intermittent fasting. This has benefits beyond just helping your weight.
It's good to find your own sweet spot for carbs. I believe you should give the low carb a good college try, get yourself adapted to it, then find the sweet spot. Otherwise it's too easy to just say "nope, doesn't work for me." It doesn't work for anybody who doesn't allow themselves to adapt to it. I'm adapted to very low carb but if I stay there for a long time, I get quiet, withdrawn and sometimes a headache. If I go into Mark's upper range, I get hungry, cranky and can't manage my appetite. I find Mark's middle range makes me feel the best, gives me that boundless energy and focused mind everybody talks about.
In my opinion, especially at the start of a weight loss program like this, the exercise isn't very important. You could just do some walking and leave it at that. But if you like Zumba or any of the other things available to you, there's no reason not to do them. The reason I think the exercise isn't very important is that you need time to adjust. The dietary changes themselves are already stressful for the body there's not much reason to cause further stress with too much exercise. Learning how stress inhibits weight loss has been one of the stranger things I've learned around here. It could explain why I could exercise myself to death in the past and stay fat and why you can eat about 1000 calories a day and see no weight loss.
Good luck to you and welcome to the tribe!
Female, 5'3", 50, Starting weight: 163lbs. Current weight: 135 (more or less).
I can squat 192.5lbs, press 75lbs and deadlift 210lbs