Whats wrong with me? help please!?

Almost everyday I feel 'sick', tired and weak its like I have no energy. I lose my appetite often and get mild headaches, I also get sharp gut pains and aches I'm constipated (the doctor prescribed movicol but I don't like it) I feel just dreadful all the time. I have mega anxiety issues to (phobia of being sick) also of food contamination. Please help