I feel the same way about college work. If I have a paper or a test that I need to work on Motzai Shabbos, I often find miyself obsessing about it, and feeling myself becoming anxious. I found that the best thing I can do at that point is to throw myself into learning, spending time with friends, singing zmiros, davening, or just going for a nice, long walk to clear my mind. Often, before I know it, shabbos is over, and I can tackle whatever assignment was causing me angst, without allowing it to ruin my shabbos.
Hatzlacha Rabbah!