You should have yourself checked for some micronutrient dificient such as iron or B vitamins, particularly if you are vegetarian or don't eat meat and other animal products very often.
bark135, you need to see a doctor asap. not eating for 4 days is not fatal but it is very unhealthy indeed. try at least to drink water until your appointment and anything that could stick to your body until then... apple sauce, vitamins drink, some are lemon flavor and easier when one feeling nauseous. also do not forget to mention the bruising as your doctor may want to have blood work done (a low platelets count is usually one of the reasons for bruising, not the only one but worth considering... it takes a platelet count to get extremely low before being life threatening but still one could go on with his/her activities not knowing that in case of an incident, his/her blood will not clot properly and internal hemorrhage will result...) so doctor visit is really what you should do right now. the fatigue if not directly linked, it definitely another symptom key for your doctor. please take very good care and do let us know.
nikita
Not eating in 4 days is very unhealthy, as is feeling sick when you eat. You need to go see your doctor.