I need to know what is causing this. I have never had a problem before. I have had her for 4 years but I have no idea how long the previous owner had had her for. I don't know if this is old age or lack of some sort of nutrients please help!!

Front legs are fine.
Back legs move a bit but she drags them behind her.
Eyes are open.
Seems active not but was sleeping for a couple of days. I thought she was just trying to hibernate.
It got really cold last night left her lamp on, but idk if it was warm enough.
I give her calcium and all those other vitamin and gut loaded crickets. Although I ran out of the calcium a week ago so she didn't get any this week.

I hope this is enough info.