What To Do For Fatigue, Abnormal Bowel Movements And Erection Problem?

38 y.o. male, 207lbs, 5'11, no medical history really, drink alcohol on weekends and cut back on smoking a lot, only have one cigerette every other beer on the weekend, always active until the last year, hit with fatigue, abnormal bowel movements, tired, abnormal RBC-low, low hemocrit, low hemogloblin, upper abdomen pain recurring and progressing but still intermittent. sexual problems with erection, none of this is me at all, I am very active. My job is very active. Is there any thing my doctor can order lab wise or than multiple scans to find more information out.