Hey. You. The new teacher sitting in your room at lunch. What are you doing? I see that you are grading papers and eating lunch, but why are you doing it by yourself? That's a terrible excuse. We all have a ton of papers to check. You cannot lock yourself up in your room at lunch every day to get work done at the expense of being with other teachers. Before long, your room will become a prison.
For all of the new teachers out there, get out of your room. It's ok to have a working lunch once in a while, but not every day every week. There are people in your department that want to talk with you and share ideas. It's the only time during the day that you will get to be around adults, so take advantage of it. Sometimes it is just nice to sit around and not talk about content. The school year is long and it can be tough to try and navigate it alone. Get out of the room and see what you can learn.
This advice is coming from a guy that spent a very lonely first year getting work done, but having no idea who his colleagues were.