You are undergoing the process of ceremorphosis, which will gradually change your body into that of an Illithid, a sadistic race of aberrations feared by sentient creatures on many worlds across the multiverse due to their powerful psychic abilities. Inside your brain wriggles a tadpole, which has seemingly undergone a change from its normal behavior. Due to this change, or perhaps due to some other force, you won't be affected by ceremorphosis like normal and will get to keep your normal personality and soul.
Through gaining the tadpole, your brain has already been altered, initially allowing for the use of abilities that others would find unnatural. The first psionic ability that you have developed would be Authority, mentally dominating those who have a weaker psionic presence than yours, delving in and out of their memories, and changing things for better or worse. The second psychic ability that you have gained is telepathy.
As your psychic abilities grow stronger, the more access you gain to the various abilities that being an Illithid grants. Such as the ability to create black holes or change into a displacer beast. Eventually, with enough time, your tadpole will fully evolve, letting you transcend into an Illithid form. This form allows you to access the full might of an Illithid being able to go toe to toe against an evolved elder brain and mentally dominate it. This also comes with a hunger for brains that will enhance your psychic ability.