I'm having multiple symptoms some including fever, severe nausea, pain in chest and left arm, bloody black stool sometimes none at all, find it very hard to urinate as well, everything makes me sick when i try to eat, vomiting blood. what's wrong??

If you are having all of these symptoms, you need to be seen in an emergency room ASAP. Vomiting blood and blood in stools could indicate a GI bleed which can be making you anemic (low blood count) and this can lead to chest pain, even a heart attack. So, you need to be seen right away, today, in an emergency room to get diagnosed and treated. Good luck to you!