Yes any time I see a change in behavior a red flag goes up.
Check her from head to toe, touching and gently pressing for signs of an injury. They do get bruised too.
Then check the teeth, make sure the front ones are nice & straight, & orange. Feel her jaw line for bumps that could also indicate teeth troubles.
Watch for any kind of wetness around the mouth & eyes. Check that droppings are normal and food consumption is good.
Has anything changed where she plays? Any new noises or smells that could be upsetting her?
And yes if the temps have gone up they will slow down. Even mine get lazy when we get what we call summer
they are so used to the cool that even up to 68-70 , or a humid day and they would just as soon lay around the cage.