Is it normal for me to feel like a stranger to my own girlfriend?

So, my girlfriend and I have known each other for almost 4 years now. We met each other in San Antonio, TX at school. We had a small flame start there towards the end but at the time, I had someone in my life already and I'm not the cheating type. After school, she went to Italy for her work, for 3 years, I went to Virginia. We kept in contact with each other during those 3 years and dreamed of the day her and I could be together. I had been through multiple, bad ending relationships in that 3 year span and about a week after she finally came back to the States, we got together and decided to turn our flame into a relationship. For the first month and a half, everything was perfect. We had a moments of disagreements but we were always happy with each other. We both work together, just different shifts, and she has been going through a lot of training, screwing with her schedule and making her lose sleep. Then the day came where we could finally have our own place to be together, which we weren't alone, my best friend allowed us to move in with her. Now, my girlfriend and my bestfriend are inseparable. They became instant friends when I introduced them to each other. So it was mostly my girlfriends idea to make the move, and justified it by getting us a dog. So now, here we are, living together with my bestfriend, who has her own issues right now, and a dog. About a day after we had moved in, like a switch was flipped, all of a sudden, I'm being controlling which I thought we had squashed but for about a week and a half, something continued to bother her. I tried asking her if she was okay or what was wrong but all I would get was "I'm just tired" or "I'm not feeling well." As true as those statements were, I felt there was something more she wasn't telling me, and I knew she talked to our bestfriend about it, so having no success of getting her to open up to me, I went to our bestfriend to see if she onew anything that would help us out because by this point, my anxiety had kicked in and I was worried it was our relationship that was having the issues. I finally find out that my girlfriend is being suffocated and needs space, so I reluctantly backed down. What I mean is, we were happy to see each other every day when we could. We had amazing sex almost every night, we spooned at night when we were able to sleep together, and there was never a problem until we made the move. Now all of a sudden, she needs space which means, I can't hug/kiss her when she comes home, I can't hold her at night, the sex completly stopped, and now, I feel like a stranger in our own house, and bed, sleeping next to a woman I can't love because she threw up a wall against me. Granted, she had some traumatic events happen to her in the past and she says that they are the roots of what is causing this, but why won't she come to me and allow me to help her through these hard times and be treated as her boyfriend? I've tried addressing the issue but I only feel more like the bad guy afterwards. Is all this normal or is there something I'm missing here with her? I'm at my wits end and I want to show her I'm mentally and physically strong enough to support her during this but I'm ready to throw down the towel and give up. We both love each other to death but it feels like I'm giving more than she is.