I'm not wondering if I lost my frame on this girl. Here's what someone else told me about the situation... I don't think you are understanding what is being said to you. You were advised not to do certain things and leave it alone... you did, look at the end result.
I get that you feel that you connected in a way that is "unmatched" but understand that only YOU feel that way about it... she obviously doesn't.
This isn't a Hollywood movie where she is going to fall in love with you and then wait for you for 120+ days until you come back... then when you arrive at the airport, she is there waiting for you. It's not happening. Stop pursuing, she already tried to "let you go" softly once.
Seriously, at this point, I wouldn't even send the postcard. I'd let her wonder... even if at all. The fact that you didn't go with her to have dinner with the roommates is NOT what killed the interaction with her. It's the fact that you were leaving for a while and she probably knew it. She probably figured she could get a bit of action and fun with you before you left and you wouldn't get attached because of it.
If she really cared to see you, she would have moved mountains to see you before you left. Read into THAT. But don't say the connection was "unmatched" for her too... when all the obvious signs point to NO.
Girls aren't weird... you are being weird about this. She's basically blown you off and still is and you think you can get the frame back? There is no frame. It's gone. She got what she wanted out of you and moved on. Your focus should be on your time away... not this imaginary unmatched connection that you mentioned.
Kinda harsh but may this be the case? Was me being congruent over the top? To bad...