What is going on...

Shelby
AF isn't due until 29th. 
I'm only 5 DPO which I know is early but I'm super confused. 
- nauseous for 3 days, if I'm sitting or laying down I'm fine.. The second I stand up I get super nauseous. 
- itchy itchy itchy breast! Like extremely. 
- bad back pain (like pms)
- weird pinching pains in lower abdomen, and hips.
- bad headaches (normal for pms)