I have had trouble with my bowel movement and I'm scared to death?

I have always had frequent bowel movements (2 or 3 a day), but for the last 3 to 4 weeks I feel like I never have to go, when I do try to go only a little bit comes out and it is soft, not diarhea but soft and actually pretty healthy looking, it is frustrating because I can not p a firm stool like I used to, there is no visible blood and I have no pain, my doctor has ordered a Barium enima and this procedure really scares me, (is it painful?) I can deal with discomfort or embarresment but planned pain is not for me, to make matters worse I have dealt with anxiety for years and I now have myself convinced I could have colon cancer, I've done research and these are common symptoms of colon cancer, I am 37, could someone please help and educate me with any other less serious condition that infrequent soft stools of small amounts could relate to? and is a barium enima the way to go? please help!