We had a similar issue with my son being grumpy last year until we grade skipped him and then he was really happy. He was in prek and switched to k for the last few months and now is in first grade and loves it. It's still easy for him but he is learning some things and is getting along much better with the other kids. I still need to advocate more but the grade skip helped a lot. We went in with gifted scores and books he was reading and math workbooks he completed. I also brought a story he wrote and some drawings. We sat with the principal and were able to convince her to have the GT office test him as well as a counselor who gave him an end of first grade exam. Our school's policy required proving the child was 2 grades ahead in order to skip 1 grade... Kind of silly. Good luck!
