My eyes feel heavy/watery/itchy. i'm concerned that it may be pink eye. if it is, how long from the onset of other symptoms would my eye become pink?

Not long: While other symptoms may precede the pinking up of the eye, usually "pink eye" (conjunctivitis) usually starts with the redness and concurrently irritation and excess tearing. So if you have watering and itching and pinkness does not appear quickly, it is more likely something like allergy. If the vision is changing, or the pain is signficant, then see your ophthalmologist.