Please help me

During traveling in metro Or if I sit in closed AC room, I often feel sudden increment in my heart beat, my hand and legs start shaking and feel uneasiness. This has happened everytime when I used to travel since last 3 years. This affect my studies and gradually I just left my mind from travelling. My Symptoms Are : *My stomach is always upset. *Gas problem. *Stool doesn't pass properly. *Always feel pulse sensation on left side from navel. *Body does not able to gain weight while I feel very hungry and accordingly eat too much. *I also feel that every thing is in front of me is rotating. *Laziness and tiredness without doing any work. *I also has fear of going on new place. Because every time I try to go somewhere these symptoms came back.