Hi danvers,
You mention ASD diagnosis. Do you mean Asperger's Syndrome?
If you don't mind my asking, how committed are you to your relationship with your girlfriend? I'll tell you now that it may be different from any other relationships you have had in the past.
Maybe she's scared? Just my feeling from reading your post and your explanation of her behaviour since you've been together. That as well as the use of the stimulants. <sigh>
You say she was only diagnosed 3 years ago, which probably means she's been dealing with a war zone most of her life (school, relationships, general day to day life) and not knowing how to deal with it all.
I would suggest reading some information that's available regarding Asperger's and women.
Here's one book...
http://www.tonyattwood.com.au/index....ity&Itemid=621
Connecting with your Asperger Partner - Louise Weston
and also
http://www.tonyattwood.com.au/index....917&Itemid=720
from the book -
Girls and women who have Asperger’s syndrome
Safety Skills by Liane Holliday
Foreword by Prof. Tony Attwood for "Safety Skills for Asperger Women"
I hope it helps a little.
[Tony's site is very large, but there's much useful information there. He's my son's doctor. My son now 24.]