Question: About two-thirds of the way into the meditation my eyes started waving, I started yawning a lot and felt a little nauseous.

Babaji:

Yawning needs to be controlled so one does not go to sleep. If the eyes start wavering, if one is feeling giddy or nauseous it may be from gas or acidity in the stomach. So delay the time for meditation to one or two hours after the meals. Too much fasting can also cause this. If it persists, then one should see a doctor.