I am not sure what the deal is but I am suspecting he has lost interest in school because he is not being challenged enough.
Where do you live? When is his birthday? It might have been a good idea to accelerate him into Kindergarten instead of going through pre-K this year. Is there a chance you can skip Kindergarten and get him into 1st grade in the fall?
My DS4 is starting Kindergarten a year early in the fall and I got him into the Pre-K4 program this past August when he was supposed to be in Pre-K3. He had to test into it. Even K4 is WAY too easy for him but he did learn some things last semester. This semester, not much...he is pretty much just "sitting out" the rest of the year.
Seems to me your son needs more stimulation in school. He might have gotten anti learning because of boredom. I wouldn't push him though. Let him be so he doesn't get turned off even more. He once had a passion for learning, that passion is still there. It just needs to be rekindled again. Focus on finding a solution for this upcoming school year, maybe a possibility to skip Kindergarten.
There are lots of more experienced people on this board than me so I hope you get some more advise.
