Sadly Yes- with in an hour some times, with half a day some times, with in a few days some times.... then I can be ok or depressed for days on end as well and then have rapid mood swings in between--- It is no fun..and everyone is different. I am working with thoughts and emotional regulations with my T right now,...
The scratching yourself till you bleed, should be something to bring up some one- it is a part of you trying to release your emotions, I think In opinion... Maybe it is not, but still that concerns me to read that from you

Right now, my t is trying hard for me to understand Safe Place and Containment.. Which is, when something upsetting comes up- I take a moment back, go to safe place if needed, but contain my emotions for what is going on to get my work done.... I am having issues with containment and keeping it in my "box" or what have you-- but it does sound like a grand idea for coping some days
Do you talk or have access to a school councilor? Or talking to your parents or someone?