My son is in kindergarten, but he is crying so much and he doesn't want to go to school. He says the hours are too long. He won't eat at school and he had a couple of accidents (he got his pants wet but didn't tell the teacher). It's only been 15 days since he's been going to school. I'm just wondering how long it will take him to get used to the long hours and what can I do to help him. I tried volunteering at his school, but that didn't help because now he wants me to stay every day.
From your question, it sounds like you've concluded that there are no real "problems" for your son at school, just that he is having trouble transitioning to kindergarten, which can be difficult for kids who are were not previously in a full-day preschool program. However, it Kindergarten is an important developmental transition, and, as your son learns to "survive" each day, it will help build crucial resilience over time. The first thing is to communicate with your son’s teacher and any other school personnel who can help. They may have some feedback about how your son is faring during the day (probably better than you think), and they may share some wise advice about how to support him. Second, don't sweat the eating part. You should have a conversation with your son about what he wants to take for lunch (if he takes his lunch) and pack options that he likes, but don't become invested in how much he eats. If no one is monitoring and pressuring him, he will likely learn to eat when he is hungry. Third, have a conversation with your son about how to have enough energy for school. Perhaps he needs to go to bed earlier to function well. (Even if he is already getting plenty of sleep, you can may still reduce complaints about being tired at school with if he knows that complaining will lead to an earlier bedtime.)
Finally, assuming that the reports from his teacher are reasonably positive and there this is just an issue with of adjusting to school hours, be careful not to call too much attention to the problem. Pay lots of attention to your son's positive stories about school, but become suddenly busy when he begins to complain. After a little empathy, gently cut off further complaints and let him know you will be happy to talk about something else. Well-meaning parental attention to complaints can inadvertently reinforce and increase the complaining! This may mean that hanging around school -- as you discovered -- is a bad idea. While you are a support for your son, it's his responsibility to adjust to kindergarten. The more he sees your confidence in his ability to do that, the faster he will figure it out.