@galeri,
You need to pull yourself together.
If this gal is that depressed, then she needs treatment. Your affection (sorry, I can't call it love if you have never, ever met) is not enough. That's not a personal attack; it's reality. People who are depressed need care, just as much as people with broken bones do.
And the truth is, you sound pretty depressed as well. You have been using this girl as a lifeline and that's nice, but it's overwhelming. It's too much. I really recommend counseling for you as well, because you need to get out and meet people, in person.
This does not mean that love can never, ever happen online. But three years without meeting should tell you something, particularly as you are over 18 and should have had the freedom to go where you pleased, including to visit her. Yeah.
Please go to your doctor and ask for a referral. I fear you are avoiding society and I suspect this gal is seeing that, too.