This problem is the result of poor leading. Your actions should reflect your intentions. If you didn't want to get super-serious right away, then you shouldn't have let her stay over four days in a row. Furthermore, you shouldn't have promised monogamy so quickly. You just rolled over and stopped resisting any kind of beta-ization. It's natural that she would start to lose attraction for you.
Read this ("relationship rules 3.0" by Tubarao):
http://www.pua-zone.com/showthread.php? ... -Rules-3-0
And this ("Summary of the beta-ization process" by Corvette):
http://www.fastseduction.com/cgi-bin/se ... 3900599449
In the short-term, you should definitely stop seeing / texting so frequently. Figure out what kind of relationship you want and act accordingly. Don't emotionally invest in her or go out of your way to do nice things for her, unless she's actually earned those privileges by treating you well. In the long-term, learn how not to get yourself into this situation again.
Just my 2 cents.
-Wolf