She'll be fine, trust me. And yes, it's very possible that she's going to molt. I've had a few that just stopped eating, but never got a bald patch and then out of nowhere molted, they don't always get that premolt look.

If you're really worried about her water, then if you're in the area by all means go a refill it, but if you don't end up in the area she'll be perfectly fine for a little bit. And I wouldn't bother trying to feed her. If she's been refusing for three weeks, just wait until she molts or at least give her another couple weeks.