It sounds like you chicken was suffering from some disease, parasite, or illness when she went broody. Loosing weight and comb going pale sounds like she was getting her blood sucked out by parasites while she was sitting on the nest and not moving about.I'm no expert, but my hen lost weight rapidly, even though I took her out to eat and drink twice a day, her comb went pale and when I managed to break her she seemed to have cramp in her legs, she was very weak and could hardly walk. She was only in there for a little over three weeks, and she had no intention of stopping. I think broodies who are not quite so serious about is as my Nutmeg would be OK though, but I heard of a hen who starved when she went broody..
A healthy hen will not come to any harm from being broody - and they will never starve. You do not EVER have to take them off the nest to eat or drink. They do it themselves. They always choose the times when no one is around and there is no disturbance. They will rush off, have a massive stinky poop, fill up on food and water, and go back to the nest.
They are really sneaky about leaving the nest if people or animals are about. This goes back to their wild instincts, where if a predator saw them leaving the nest unguarded their eggs would be quickly eaten.
If you OPs hen is broody you can just leave her - but I think its better to use my easy breaker technique so things go back to normal:
1. Put the hen in a cage / crate, which has a wire bottom (not a solid floor).
2.. Add a roost , food and water.
3. Keep the crate out of site of her nest or you can cover the side that she can see her nest from.
4. After 4 days let her out - she should be back to normal.
TIP. You can block off her nest box, in case she gets the urge to go back into it after you let her out. You only need it blocked a couple of days.