Sliven,
What you cannot have is always more desirable.
Don't go offing yourself because of someone else, not a good plan.
Just tell her in the nicest way (don't do a guilt trip on her) that she is very special to you and that in fact you are in love with her.
Don't let her know that it makes you feel bad or if you already have, then let her know that you are ok. Then cheer yourself up and get on with your life.
Keep in touch. Be patient. If she really likes you you may get a supprise someday. You have a lot of life ahead of you. Be cool. Have fun. Things will come to you, lots of things.