This really does sound confusing, so I can understand why you feel as you do.
I am guessing that losing her Mum, plus her Dad being disabled, and then being ill over Christmas, has probably affected her ~ but the rest I cannot really understand.
The only thing I can think of is that she really thought of you as the 'love of her life' and that this scared her, as she is only 19, and 'not ready to get serious'.
I am wondering about: "i cant handle this"
I wonder what, exactly, it is that she can't handle.
Is it the fear that, though she feels that you are the love of her life, she worries that you will let her down??
Is there a problem in her family, or elsewhere, that you don't know about?
Perhaps she needed to talk to someone about her feelings ~ hence the meeting with the friend.
It is unusual for a girl to go from thinking that you are the love of her life, to ignoring you completely, unless she has problems of some kind.
You could try writing her a letter.
You could admit to being confused by her actions and assure her that you do not want to pressure her into doing anything that she isn't ready for, etc, etc, and give her time to read it, re-read it, think about it, and make her decision.
Maybe, if you are patient with her, you will be rewarded with her friendship at the very least.