Lack of courage, fear of dying. Which specialist to look for?

Good evening, Doctor. for some time I have felt a lack of courage, my heart is racing, I do not feel like going out or doing my daily activities, I feel tired all the time, even when I do nothing. I'm scared to die, I'm on the bus or the subway, and I wonder if there's going to be an accident. In recent weeks it has become so severe that I resigned from work, because I am very afraid of dying on the way back and forth. I cry constantly for any reason and I think I have cancer in the intestine because I feel constant abdominal pain and as an uncle of mine died 3 months ago with this type of cancer I think I have too but I am afraid to seek a doctor. I'm afraid I'm developing a depression. What kind of specialist should I look for?