In general I agree with both posts above. On the one hand you have increased the training. Have you also changed shoes recently?

Maybe the additional km's are also contributing to a gait cycle that has slightly excessive pronation (hence the orthotics comment). That might be a "bandaid" of course if the pronation is due to more proximal issues about the hip joint (stability, fatigue resistance, ability to extend and recruit glutes and hamstrings etc etc).

As you're a physio student now is a great time to get looking at the body. Get a friend to video you running towards the end of a run when things are perhaps falling apart slightly. This might provide more insights into the issues.

Oh and don't forget to eat well