Heya,
Yup agree on checking your iron level, it could easily be low and you wouldnt know, but dizziness is a syptom, also get your D checked, really sub-standard d levels can cause dizzines.
I would say drugs, but sounds like you ruled that out, usauly leaves a defieciency of some kind, cant hurt to run some blood tests and at least narrow down the cause.
Thanks Jon