1.
You're Unhealthy
You can't expect to feel good if you're filling your body with junk food, skipping meals or eating too much or not enough. Healthy eating habits are a key part of feeling good and just as important as getting enough sleep and exercise. Your body needs vitamins and minerals to function properly.
Yeah, it might sound like a lot of work to stay healthy but if you want to get the most out of your body you need to give it the best. If not you may end up with serious issues like high blood pressure, diabeites, and heart disease.
Stop drinking more and more coffee so you can keep going, instead get enough sleep, eat a healthy breakfast, take your vitamins and get some exercise. After a while you'll notice that you have more natural energy and actually feel happier. Give it a try and see if being healthy makes you feel better.