Nate started full-day kindergarten last week (Wed.). He didn't have any problems and always said that he liked school and that it's fun. Today he cried when we got there saying he wanted to go home. As much as my heart broke for him, I knew I needed to leave him there. He was fine after school was over. I tried to ask him why he was so upset, but he didn't have an answer for me. Now that it's bedtime, he's getting all worked up again saying he doesn't want to go to school tomorrow. When I ask him why, he just says that he doesn't like it. I have no idea what to say or do - he is our one and only so I have no previous experience with this. HELP!!!!!

I really don't have advice either because we never went through this. I think you're a SAHM though so the first week might have been fun and now he's wishing he was back at home. I would just continue to talk to him and try and get him to discuss the things he does like - ask about friends, recess time, what's his favorite part of the day etc?

I would probably email/send a note to his teacher and explain how your son is acting at home and ask how he is acting at school and if she noticies anything going on.

Yes, the novelty has probably worn off. Matthew cried almost every morning of preschool this past year. The anticipation of separating from us was too much for him. However, once they actually got to school and dropped him off, he was perfectly fine. He never cried to go home once at school, and always said he had a great day afterwards.
We tried a ton of different things (after talking with the teacher and director to make sure he was really ok at school) such as talking to him about the fun parts, his friends, being a big boy, etc. but ultimately what worked the best was recognizing, then kind of downplaying, his dismay. We also did a lot of practice and rehearsal which worked after a long time.
"Ok Matthew, let's pretend it's morning. You be you, and I'll be me. You know you always have a great day at school, so when I say 'it's time for school!' you say 'ok, Mommy, I'm going to have fun playing with _____.'"
We found that the more we dwelled on it, the more undone he became. For us, it was almost like we were confirming his distaste for going, if that makes sense. It's kind of tricky, because you want to recognize and appreciate their feelings, but at the same time, you don't want to let them envelop themselves in them.

My daughter is our one and only also and we found / find that after the weekend or a school vacation she tends to not want to go back to school either. It's really tough to deal with and my heart breaks for her sometimes, but the more I showed her it bothered me the more she carried on because she knew it was getting to me. I just reassure her she will be ok and if she wasn't ok they would call me. I also tell her I will be there the minute school is over to see her again. One of her friends is an only child also and her Mom said the same thing happens with their daughter because they spend the weekend together and she hates that come Monday the parents go back to work and she goes to school and after care.

My DD does have trouble with some girls in her school so that makes it even tougher for me, but I'm told she is "safe" there even though she's been punched a few times by 2 different girls. Grrrr!