Girl lost interest??

I don't understand but I think this girl lost interest in me, basically last Saturday we met for the first time we went pub with her friend and it went really good we spoke the whole time no awkward silences it was great, she then held my arm as we walked to hers and kissed on her road, she was saying she really missed me and so we met up the next day at night just to see each other again kissing, Monday we were both busy but we met again on Tuesday and it went well she took me to her work saying I'm the first guy she has took to work and we then tongued when she left. Wednesday and Thursday we didn't see each other as we are busy but Friday she came around my house and we laid in my bed together cuddling and watching TV (nothing was really on to watch) she wanted to leave quite early because she didn't want to be rude and stay for ages but we tongued on two different occasions in my room and then when I walked to hers we did it twice but on the way to hers she said it was nice to be in the warm even though we didn't talk much (I asked her questions but she was rarely replying I then said to ask me questions and she goes it don't matter watch TV) How could she of lost interest in me? While laying in my bed we done nothing sexual but she did grab my penis through my trousers to see if it was hard because I was grabbing her ass and playing with it, and she also sent me a dirty picture like a couple days before, when I got home she seemed really different through texts and same yesterday when she is at work she is normally like I miss you and yesterday I said wish I was there too make it better she didn't reply and so 5 hours later I asked her how work is and she just put crap. What can I message her saying? Last night we kinda spoke and I told her to text me in the morning when she wakes up but she has not :L