Whats making my teeth look very small?

Depends: Have they always looked small? Are they fractured/broken? Do they look short or small in width? See your dentist.

Two options: If they appear to be getting smaller, you may be grinding them very heavily and need to get to your dentist for a night guard and possible other treatments, otherwise they are that way because of genetics.

Small teeth: Some people have naturally small teeth, a genetic situation. Some people have overgrown gums, making teeth look squat. Some people have decay between teeth making teeth look narrow. Some people have excessive biting edge wear, making teeth look short. See your Dentist. An Orthodontic, Restorative, or combined resolution may be advantageous.