What Causes Dizziness Mainly During Periods?

I have had dizziness for 2 months now and it seems to get worse during my period I received the depo shot twice last one being a week before all this started. I also have one pupil that is always dilated more than the other I've been to the er 4 times been to an eye specialist and cardiologist all my blood tests and ct scans have came back normal. Any idea about what's going on?