yeah when i was on summer break i used to sleep in, wake up check the mail and go back to bed.
it isnt uncommon to get a little melancholic or depressed especially with a change in structure or routine, which is what universit/school is good at providing...no template to follow, we tend to get drawn inwards, introversions and as you describe become funked out.
i really think it is a necessary compensatory adaptation most AS need but are not aware they need it, i call it decompress time.
you want out of it, but your mind is saying...no no stay here, i need to re-charge.
dont fight it man.
unwind, relax, funk out, and recharge for the september semester.
hope this helps.