Cat chasing shadows

Hello yall, I have an issue with my cat. So a while back my partner and I got my cat a Lazer pointer, we tried tl end play with a physical toy but he had zero interest in it and since then he's been chasing shadows like they owe him money. He has absolutely no interest in toys or treats and will pounce at a small flicker of light or again, shadows. Im worried about him and would love advice about what to do to help. If its any help he's 3 years old and we're only had him 5 months and this has only started about 3 weeks ago, after the Lazer pointer