Lizard won't eat - always sleeping

My female Western Fence Lizard (Sceloporus occidentalis), Spike, has in the last month, become more lethargic and less hungry. She has plenty of light and the temperature of her terrarium is fairly constant at 73-76 degrees. She seems to have no interest in the live crickets (her usual favorite diet) we supply her or in staying awake. My question  - Is this a temporary winter mode she has gone into or some health issue? I got her last April - so this is the first Winter of caring for her. Thanks for any advice or information you could pass on.

[AndiJ78]

Does she have the right light? Is it a fresh bulb? Oftentimes that will shut them down as they cannot metabolize their intake without adequate amounts of UVB.

Some reptiles will brumate, but it is not encouraged unless you plan on breeding.

I would evaluate temps and UVB (even the best bulbs need to be changed every 6 months) and make an appt with a vet. You will want to find one proficient in herpetology. Their metabolism is much slower than  ours which means when they get sick, it is harder to treat it quickly.

Also, how are the temps? Calcium supplementation?