Funny thing, this my last streak, I've been getting exhausted late at night, to the point where I even fall asleep before doing my nightly prayers. On the other hand, the problem is waking up too early, and specially struggling with persistent morning wood.
I don't know I've been getting that way, as I haven't been doing anything too harsh during my day, but its probably because of lent and a restrictive diet, just cutting my energy away.