Is an altered perception of time (e.g., where it goes by faster than you think) considered a hallucination?

If you are busy and you lose track of time, that is not considered an hallucination. So, it depends exactly what you mean but if this is what you are talking about, it is not an hallucination. If you are referring to something else, you could always ask your doctor to see if what you are referring to is an hallucination. If it is, a psychiatrist can help. Good luck!