I should really start doing some school work

I am definitely not working as much or as hard as I should be. Most students here spend their days studying (believe me, it is true. We had to come from our Yosemite trip early because some people had a lot of school work do to on Sunday and people even brought books with them and were studying on Friday evening! And I know people who went to Vegas and spent the weekend in their hotel rooms studying!).
And people go to networking events and workshops and look for jobs actively.

I, on the other hard, spend my days running, swimming, biking, playing volleyball and playing on computer. Not good. I am starting to feel guilty.
Foe example today, I left home at 8:30am, had class in the morning, then swam during lunch break, then another class, then run 6 miles with group, then volleyball match (which we won. Ok, the other team did not show up:)) and I got home at 8:30pm. And I have not done anything "purposeful or worthy" (as some people might put it)

I mean, I am not failing classes or anything, I still get my work done, but it could be better.
But I am not looking for job/internship although I should.
And have not started my master thesis yet.
And need to submit 30+ page internship report soon and have not even started. (Honestly, I have no idea what to write there. My internship was only 15 weeks and French students usually do 12 months internship so they can write 30 pages, but me...And school does not want to change it for me. )

But I prefer spending my days running, swimming, biking. Who would not, right?

But I am thinking, this is my last year as a student (unless I decide to go to law school), then it will be work work work work until I die. So I should enjoy it now, right?
And if I do not find internship starting in January, no biggie, I will just go back to school in France and finish my degree taking classes instead of getting work experience. (Although I would prefer working to studying.) So I am not that pressured to look for something. So I can have fun for now.
I only need to find someone who is going to do my homeworks now and offer me a job in June...

(I hope this is just a short phase and my conscience will shut up and left me do my fun stuff guilty-less.)