consider: exploration/exploitation. Maybe some part of you has decided that it's time to stop exploring education and its time to exploit the knowledge you already have? Do you feel like you have a lot of knowledge now? Or that you know enough? Is your relationship to knowledge seeking now in the form of "disinterest", "too busy for it", "sick of it" or some other sentiment...
(also as Artaxerxes said - depression, or other brain chemical things that this could be a symptom of)
In our college, students of the first four years were rumoured to be going through the exploration phase, and then - satiety and exploitation. It certainly felt that way to me, and anecdotally a person a year younger, but of course it might be just because of specific curriculum structure. (I am a botanist.)
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
Notes for future OT posters:
1. Please add the 'open_thread' tag.
2. Check if there is an active Open Thread before posting a new one. (Immediately before; refresh the list-of-threads page before posting.)
3. Open Threads should be posted in Discussion, and not Main.
4. Open Threads should start on Monday, and end on Sunday.