{{Gris}}so sorry - between your year and Emily's year I'm really surprised at how many teachers make it past the first year. I wish I had real words of advice.
I have lots of words of advice, but I don't know if they're helpful. There is a reason that 50% of all teachers leave the profession (note: not the school, the entire profession) within the first five years. A significant percentage leave after that first year for many of the reasons you are citing. Sigh. I'm a huge advocate of public schools--was educated in them, had two public school teaching parents, and taught eight years in a public school myself--but when I moved to California, I went into the independent school system because I wanted to be the best kind of teacher I could be, and I knew I wasn't going to be able to do that with huge classes and an overwhelming grading load. I felt guilty for awhile until I decided that I was beating myself up for something that was not my fault. I put almost a decade of my life into public schools, and the problems I dealt with were almost always external (overcrowding, student apathy, parent issues, etc.). Ultimately it is important to realize that teaching is a job, not a divine quest. (A hard-learned lesson for me.) Like any job you give it your best, but if it's not a healthy situation for you, you have every right to seek a better place.
I want to encourage you to stay in teaching regardless of what you decide about this particular school. It does get better. The second year is easier than the first, and the third is easier still. It never gets "easy," but it does get more managable. And even in a school with many problems, there are many times when you will feel exhilerated by your students and by the work you are doing. But I need to reassure you that what you are feeling--that doubt you are having about your own abilities and effectiveness as a teacher--is completely normal. I cried more times than I like to admit my first few years. (And for the record, showing emotion does humanize you, but try to avoid crying if you can. Leave the room and compose yourself and come back. Tons of reasons for this that I won't go into, but it was another hard-learned lesson.)
And yes, the first year in particular is its own circle of hell. It will never be as difficult as it is this year. Hang in there. Don't give up on teaching just yet.