I have a really bad headache & it gets even worse when i try to bend , stand or even move to fast i been having a fever of 100.3 should i see a doctor?

Context important: ...but you may be describing dehydration with postural changes. Drink up on the fluids as tolerated, but if can't take oral fluids well, or symptoms and fever persist/worsen, please visit your provider or even the Emergency Department for a check of orthostatic vital signs, treatment of the underlying febrile illness, and if needed IV fluid and electrolyte repletion.