Your body tells you that you need more energy. Take it as warning and make sure you are eating enough. If your goal is weight loss then that is a slow process and you need to be patient. Trying to rush things will not be sustainable (as you just noticed!). Remember it is a marathon, not a sprint.
It sounds like you were very close to fainting. I used to faint a lot when I was a teenager as I was tall and very slim, it always started with dizziness and feeling sick, then my eyesight and hearing would go and at that point I’d pretty much black out but wake up after 15-20 seconds. I would reduce your fasting window and gradually build up to it, but I would agree that your sugar levels and most likely blood pressure were low
Going from 16 to 22 is a huge jump. You should see a doctor regardless, but in the meantime don’t do anything crazy, 16h is fine and increasing by 6 hours out of the blue is a bit much (your body seems to think so at least)