Enjoy the chocolate, either this Shabbos on Shiva Ossor b’Tammuz, or Shabbos in 3 weeks on Tisho b’Ov, or of-course in the 9 days when you shall be deprived of juicy steak & meat.
Have in mind that you are eating it to have more energy l’Shem Shomayim, and then go & do some learning with that burst of energy.