WALK ALONE: Please go to your primary physician and ask for help. Tell him/her that your parents don't recognize how serious your feelings are. Because some antidepressant medications take weeks to help --- ask him/her if there is one of the "old" type meds that you can use while you are waiting, because they tend to take effect almost right away. Ask to get right in, instead of having to wait. Don't be shy about saying that you feel it's an emergency.
Also, if you feel okay about doing it, speak to a school counselor. Sometimes they can be very comforting.
I'm very glad that you posted to us. Many of us have felt this way. We understand. Sending you good thoughts. I can promise you it won't always be like this. Sorry it's so rough for you right now.
Adieu