My stomach is constantly upset. it gets worse with exercise and i get really fatigued. when i took ibuprofen i felt fine. been going on for a while?

Anxiety: I feel empathy for constant upsetness of your stomach. At age18, pressure from parents, separation, breaking up of relationships, school, peer pressure, and finding your identity can cause upset stomach with butterflies sensation, knots, nausea , heartburn; and fatigue See a Physician for diagnosis and Therapy for relaxation, to resolve conflicts and to, develop coping skills for stressors

Gastritis: Sounds like gastritis and actually may be caused by the ibuprofen. Start with prilosec otc for a couple of weeks and see if it improves. Otherwise you may need to be examined and possibly scoped. Also try to log when symptoms start and stop and what foods you are eating.