You're right, I do have a low self esteem, in fact I've been having it my whole life. And no, I don't think it's the case.
It would be a little difficult for me to be honest since I'm paranoid.
I don't act like I'm depressed while at school, so what if my teachers aren't going to believe me? Most people see things only on the outside. In addition to that, whenever I want to go home earlier, my deskmate wants that too, so it'd look weird if we both asked to leave.