Hi Spantoh, is your GF in a recovery program since she left treatment? AA, counseling, etc? Are you in AlAnon, counseling, etc?
I have been with my RABF for 10 years, and he is sober 6 months, so I get where you are right now. The first few months after he returned from treatment were difficult for me. I didn't know exactly what to do. He seemed to keep some emotional distance as well, while I wanted to work on us and talk! I learned through AlAnon to let him work on his recovery, and that I could stay focused on my own recovery. As we both gave each other space to do that, we ended up doing better together.
80 days is early, I would offer that you give her the space she is requesting, and work on yourself during this time. Now.....if she remains distant as time progresses....that's different IMO. If you're staying together, at some point you'll both need to work on building the relationship again.
Kudos to your girlfriend for 80 days, and I wish you both a happy future.