Right this is what i do/think you should do.

By the sounds of it, you are working very hard. Is your mother dependant on you in any way? Like cooking and/or cleaning? If so go and stay at a friends for a week without telling her. That way she will be forced to do it herself and she will realise how much hard work it is and how stressfull it can be.

You could also go for a walk, completly by yourself and just evaluate things. Find yourself a favorate spot and just go there, it will be your place. You will feel alot better thinking about things in an area you are familiar with without having the pressure of your mother/friends. Pick a spot that is remote, but not so remote that it's dangerous, that way, if you do feel you are going to "break-down" it is semi-private. No one will be around to judge you for it. I personally walk 45mins to the beach and relax. I normally go at about 2am and get home at 6am.

Lastly, if you are uncomfortable with telling friends or teachers or whoever about what you are going through at home, then like already said, talk to someone online. That way the person you talk to is not going to ever meet you so you don't have the pressure of them judging you. I also personally find i am able to open up more online because there isnt the whole face-to-face interaction. I feel less intimidated. Things will go at your pace aswell, if things are moving to fast or you are getting really upset then you can simply turn your computer off, whereas face-to-face its much harder to suddenly change the subject or tell someone to forget about it.

Hope i have helped, even if i havent helped you i hope this helps someone.
-Shane.