Is it ok to give less attention to a girl that rejected me but is always talking to me?

[Dan L]

This girl in class misled me through some flirting and we talk extremely frequently. I though i had a good chance but was rejected after i ask her out. We agreed to remain friends and pretend that nothing happened, but its been hard. I really still like her alot but when we're alone, theres really nothing much i want to say. I tried distancing myself from her but she in turn started to text me about small little things. I still reply her but nothing more than just acknowledgment but she will make me ask about things and she will end it with one word replies. I feel like she just wants my attention whenever she feels like it and im a sucker for it. However just today, she was telling her other friend how she cant stop thinking of this boy in maths lecture, wanting to see him... She also told me how she found (in a total 3) guys cute, and most of the time I really dont think they are (maybe im just jealous). What can i do? I am stuck with her for lectures for another 6 months.