I am experiencing fever (worsened by: hot weather, dehydration (fluid loss), exercise or physical activity) (better by: with fluids, rest) (severity:?

Needs to be checked. We can not tell about the severity of your dehydration.If you have fever and fluid loss by perspiration and physical activity.You need to replace the fluids containing electrolytes to correct the dehydration.Severity only can be determined by examination examining mucous membranes,skin turger,urine output and by blood examination for electrolytes.Since you have fever and fluid loss,get it checked.
Unclear . It’s not clear how long you have had fever and if your symptoms are new.

Did you have a fever once or do you have frequent fevers?
can’t tell if you become warm with exercise (which is normal), or if this is a new infection or other issue.