I get how worried you are, but with a clean scope, it is almost impossible that anything super serious is wrong (ie - cancer). That said, make an appt with your Gi doc and let him know your symptoms. If nothing else it will make you feel better if a qualified doc tells you that you are OK - which again is likely due to recent colonoscopy.
diag. Stage IV, 5/05, liver met
lap sigmoid colectomy, 6/05
6 cycles Xeloda/oxaliplatin/Avastin (NED after 2)
11/08 9x13mm right lower lobe lung nodule; removed via VATS 4/09
6 cycles Xeloda + Avastin
Avastin only 10/09-5/11
Still NED 06/18