welcome! When I first started Lithium I went manic for a few days then things settled down. Maybe the same will happen with the hallucinations. Have you had hallucinations before? Could it be a coincidence in timing? You should definitely contact your doctor asap to let them know what is happening. Hallucinations can be terrifying. I really hope yours pass soon. Keep posting if it helps. We are all here to support each other.
__________________
Bipolar 1 with psychotic features
PTSD
"Phew! For a minute there I lost myself."
'Karma Police' by Radiohead