for me, it takes several weeks to adjust to higher mileage in such a way as to get the intensity up. you can still do that, but what you need for this season (aside from long-term thinking) is to increase the intensity while retaining the mileage, which means that you really push your 'workout' days, the tempos and track work and hills, but really make sure to do real recovery miles, very slow if necessary, and go progressively faster on the long run. also, get plenty of sleep if you can. no doubt academics mean you have to work a lot, but try to be efficient about it--i.e. you study in a place where you can concentrate 100% and you'll get more done in less time.