First off, 2 weeks without sex is nothing. Dry spells can go on much longer than that - and likely will as you get older if you stay together. (Of course, I'm basing this off of my own life / relationship). She has all the power to determine the frequency - and will. You can influence things by making yourself more desireable, but ultimately all you can do is go along with it or not when she has lower desire than yourself.

Secondly, it's very early in the relationship for this to be happening. For this to be issue at age 22 raises my eyebrows. That's prime hormone time. The lack of desire at this early stage doesn't bode well for the future.

Third, some might argue that all of the going out of the way to do special things for her might be counterproductive. It's beta behavior, and might be triggering something unintended in the way of less attraction. As an experiment I'd suggest doing everything you can to up your quality/status - work out, go out more with your friends, pursue your interests (she can come along, but it's clearly your outing), self improvement stuff generally. This is light dread game to let her know you're not captive and are creating options - and see if increases attraction levels. Don't be mean or overt about the process of taking time for yourself, but it's likely she's attracted to the strong independent parts of you, and less attracted to "nice" you - and you might be overdosing on the "nice."

Anyhow, just and idea, but that was my impression when reading your post. You can only invite a girl into your life, and she has to want to be there. Once you start negotiating terms you've already lost.