My BD has not been eating for the last two weeks and is spending most of her time in her hide. I have been quite worried about her as she seems so sad

but have just realised that she may be brumating?
If she is, what should I be doing? Do I just let her be?
Do I keep the lights on during the day as normal or keep them turned off.
What temperature should her tank be? She has a heat lamp (no light) that runs on a thermostat that is always on.
Do I try to feed her? Should I bath her?
How long can I expect this to last?
I understand brumation is quite normal but it is also quite worrying.
By the way, she is 17 months old.