Possible causes of elevated CA125 scores after chemo completed

I was diagnosed in August 2004 with Stage 1C ovarian cancer. CA125 at that time was 248. After six rounds of chemo, scores dropped quickly--135 after surgery, 50 after first treatment, 10 after second, etc. Finished treatment in December 2004 with scores at 10-12 levels. My Doc said my changes were 85%-90% against reoccurence because of the way I responded to treatment. Now almost a year later, the CA125 scores have started to rise. From 12 in July to 25 in October and 33 in November. PET scan in late October was clean. During this same time, I have been experiencing a number of intestinal problems--a bout with divirticulitis (ongoing) and a bladder infection. My Doc said we would test again in December and if it was elevated again, then he'd do a lap. to look for cancer. Could my intestinal problems possible elevate these scores?? Has anyone else had a similar problem? Or are these intestinal problems a sign the cancer is in fact returning? I have read that if CA125 scores double and continue to rise, there is almost a certain chance the cancer is returning. I am just looking for any sign of hope at this point.