First of all, sorry that happened to you. I've been there. Almost exactly the same situation with the same outcome, even the reach back out followed up by ghosting.
Women who have a messed up family and poor upbringing without love are literally unable to receive love and form emotional connections. When you date them, it actually seems the opposite is true at first because they love-bomb you. They are likely to tell you they love you just days or weeks into your relationship and they say things to you that leads you to believe they are enamored with you. This is because they CRAVE that missing love they didn't receive growing up and it feels so powerful and amazing to them. The problem is that it is not sustainable for these women. It's like drinking alcohol: Drink for a few hours and you feel great but keep drinking for 24 hours straight and you feel like sh*t and want to die. This is how it works for these women. After some time (could be weeks, could be months, but it's generally 1-3 months), they panic. Something "doesn't feel right" and they "feel overwhelmed". They feel a pressure and an expectation to respond equally to how you are treating them, but they feel unworthy and incapable of doing this (due to their upbringing) so it forces them to question why that is and what it means to give and receive love. That is a VERY difficult subject for someone to address and requires years of therapy and a willingness and desire to face the problem head-on. Unfortunately, the vast majority will not seek therapy and face their demons so instead, they will turn to distractions like serial-dating, drugs and alcohol, or pouring all their focus into a goal-oriented hobby/sport of some kind.
This is a really good read that I think might help you (especially if you have been drawn to damaged or needy women before like I have):
http://www.doctornerdlove.com/white-knight-syndrome/all/1/
At this point, you must stop caring why she's not on social media, talking to friends, etc. You must move on with your life and never look back.
You cannot help her and she will bring nothing positive to your life. One thing I can promise you is that you WILL ultimately come to this realization. You can choose to do it now or prolong your own suffering by waiting. Life is too short. We aren't here for very long. Don't waste another minute of your life energy on her. I know it's easier said than done but I've been there and know from experience.
To avoid this in the future, in addition to doing a better job of screening women you meet, I'd pace yourself more with women. No buying vacations and trips and things like that until the the 6-month mark. No grand gestures, gifts, etc. You should treat the woman as an equal, not someone you have to court like in an 1800's romance novel. That can be difficult because when you really connect with someone you are having sex with and your brain is dumping feel-good chemicals into your bloodstream by the truck-load, it's natural for a guy to want to buy gifts and make gestures etc, but this nearly ALWAYS backfires and as good as it may seem to feel, it's actually neediness and represents a loss of focus on yourself and your life outside of your relationship which is a huge turn-off for the woman and is bad for you because you need to remain centered in yourself and your own life and mission and goals.
