My 8 yr old daughter has been complaining of feeling dizzy lately. what could be causing this?

Dizziness: Get her checked up . Sometimes simple things like dehydration , ear problems can cause dizziness . But need to be checked thoroughly . Anemia also can cause these symptoms .

Hard to say: This symptom is not specific to any particular problem. Issues could vary from poor sleep habits or nutrition to vertigo or an infectious process. If it persists after your initial interventions you need to visit with her doc & get it sorted out.