I have one eye smaller than other it feels heavy now. Is this a deformity? (Photo)

The main cause of asymmetry is right upper eyelid ptosis (droopy) which causes the same side brow to go higher in order to help lift the droopy eyelid. The right eye effectively appears smaller. You are a candidate for right upper eyelid ptosis surgery. See an oculoplastic surgeon.

This does not make it to the level of a deformity.  This is a normal variation.  I suspect that you are no where ready to have ptosis surgery.  You can consider being assessed by an oculoplastic surgeon.  The American Society for Ophthalmic Plastic and Reconstructive Surgery maintains a directory that can assist you in identifying a highly qualified oculoplastic surgeon.

You have a condition called ptosis (droopy eyelid).  You need to see an Oculoplastic surgeon to figure out why you developed the ptosis (were you born with it, did you have trauma, age, etc.) and then an appropriate treatment plan (usually surgery) can be implemented.