He could be really busy with visiting family, doing errands or chores around the house for aging relatives, or seeing old friends, or whatever. Maybe he wants to wait until he is home and has privacy, and does not want his family to be involved in his love life. I would suggest you wait until the 2nd or 3rd to email or call, maybe send a "Happy New Year" email on the first.
Just because you have not heard from him does NOT automatically mean he "isn't into you."
Personal anecdote: I met my DH at a party after Thanksgiving. We talked for hours but he didn't ask for my number, I figured he wasn't interested in anything more. Fast forward two months, my cousin and another friend were talking about how DH was lonely and needed a nice girl to date, I said I didn't think he was interested in me, and cousin and friend told me he was just really shy. They planned another party, made sure he was there and I went, and I asked HIM out. Later DH told me he NEVER asked for anyone's phone number, he was worried about being rejected. I was pushy, I made the phone calls, I said let's go out, or come over to have dinner. End result: We got married a year later and it will soon be 24 years.
joy in Virginia