With time, the cat will adjust to the changes. They grieve over losses much like people do.
I would give him some time to get used to being alone with you and then everything should return to normal.
If you feel comfortable with getting another pet, I would suggest that you visit your local animal shelter and adopt a buddy for him.
It could provide hours of fun and will help him not to feel so homesick.
Animals adjust well. Feel confidant that your decision to move out on your own AND take your cat was a good one.
Congratulations and good luck!