Elin95, you are so brave for sharing your story and for asking for help.
I've read through the comments. Filling your time with activities and hobbies are all positive solutions.
The thing is, these hobbies only distract you and don't solve the problem. Your obsession for this Teacher distracts you from you, to the point that you're not you without her in your life. She is almost like a life-preserver. Without her, you will sink. (this is my impression)
If you'll let me, I'd like to offer a suggestion. This would be incredibly hard, devastating, but it would put a very real wall between fantasy and reality. This could be the start to a new life, that would include :focusing on you, exploring your options, interests, likes/dislikes and future. Okay here it is...what if you emailed your Teacher? Thank her for being kind, intuitive and helpful. You will never forget her kindness... Then, delicately explain that you care for her, but you need to stop emailing and all contact. You can tell as much or as little as you want, but end it with, "Even if I email, please do not respond." (You might want to leave out the thoughts of suicide. This could bring on negative attention.)
This would force the attachment to come to a halt. I realize what I'm suggesting would be incredibly hard for anyone, but you have demonstrated in your comments, a willingness to get better and longing for this to end.
Your safety and wellbeing come first, so I don't want to suggest anything that would cause you to do physical harm to yourself.
Sending you love and light. Follow your intuition.