My pregnant girlfriend just left me and now acts like nothing ever happened?

so I'm searching for answers and I don't know how much space i get here so here goes as quickly as I can. I met this woman who i've been dating for 3 months now up until a week ago, the relationship started off very intense and we ended up moving in together 1 month into things. i knew she was fresh out of a relationship and I was over a year out of mine. She is 26 and i'm 36, so we are very intense the first 2 months and we find out that she is pregnant (i'm 99% sure its mine and she says it is as well). We had unprotected sex and were irresponsible, but both seemed very excited about the idea of having a child considering the circumstances.

as the relationship grew to be more intense, i asked her if she thought that this was a rebound relationship and that I was afraid because i'd been burned before, this was in the beginning. (sorry if i jump around, i'm a bit a mess right now) so over the 3 months we are together we spend every waking moment together outside of working, i meet all of her family, she meets all of mine and she tells me she loves me and wants to be with me and that i never have to worry about being hurt. now i was hesitant at first but it felt right with me so I went with it.

to back up a little, we dated for less than a month and she started staying over all the time and by month 2 was living with me, by month 3 we were 9 weeks into the pregnancy and i'm starting to notice the hormonal ups and downs that we both read about together and she begins getting very distant from me, when I try to talk with her about it she says its the hormones and it will pass. so i try to be patient and say ok, just let me know when you're ready to talk if you would like and i'll be here, but i don't want to pressure you.

we go through thanksgiving with her family and she tells me how happy i make her and posts on facebook it was the best christmas ever! Then a week after christmas i come home from work and she tells me "we need to talk" she then tells me that she "can't do this and needs to leave me" telling me she cant ever love me the way i love her. i'm of course blindsided, thinking that the distance that had been building over the week was just do to the hormones as she told me, never did i see this coming.

I tried to be understanding and say that i know things are moving fast and if you feel we should live apart that is fine, i just don't want us to break up for the wrong reasons, meaning if she was feeling panicked by the speed of the relationship and the pregnancy, i totally understand that. what happened next shocked and hurt me so bad i'm still a mess over it. on the night she left she text me and said that she loved me and said she had a lot of things to sort out but if she wanted to come back would i take her? of course i said i would that i loved her and understood if she needed some space.

now knowing that i was crushed, i broke down in tears a few times and told her that i didn't want to break up and that i loved her, why would she come back a day later and get her things and act as if nothing ever happened? she actually was smiling and cracking jokes? this weekend was a week later and i was nice enough to take several of her other things over to an apartment that she is renting and drop them off. it was very obvious that this was really hard for me and i was mature about it but she could definitely tell i was upset. why would she show me her apartment like i was one of her girlfriends and laugh an joke about trivial things, she even at one point asked me if i did anything fun this weekend. i'm thinking to myself, my world is upside down, the girl i love just left me and is pregnant with our child and she is asking me if i did anything fun this weekend. i'm at a total loss at this point and don't have a clue what to think.