You seem to be going through a tough time. It seems that she was the only person who you could trust and lean upon and your life was revolving around her. In such cases, which is quite common at your age, a breakup usually happens if it's one sided love or you become too dependent on the person.
Next Steps
Please see a counselling psychologist for an evaluation and further course of action.
Health Tips
If you are still suicidal then you must see a psychiatrist in the emergency department of a nearby hospital immediately.