Waiting to see what's wrong with me.

Hi I am a sixty year old Male and I am now under the Colorectal dept of my local Hospital. Things started about 10 weeks ago, my bowel habits changed from constipated to runny almost overnight. Maybe I should give a brief background. I have suffered with Depression for around 14 years, I also have had Angina for around the same amount of time. Last September I was referred to Vascular Surgery (I have a blocked Aorta where it branches by my legs) by Rheumatology (I have Rheumatoid Arthritis). Anyhow I went to my GP 10 weeks ago as I had Stomach pains and was runny. I had a FBC and gave a sample of poop (which they lost so I had to do another one). The results came back negative, still my Pains, which are mainly just below my belly button and out towards my sides got worse and my Bowel habits were still the same I went back to the Doctor who referred me to Colorectal, within a day or two I get a phone call inviting me to have a Colonoscopy, I had a bad experience with that procedure before so I managed to get a Virtual Colonoscopy done. I now wish I had an ordinary Colonoscopy done as I there is anything found on the Virtual one I will have to have it done anyway. I have looked at the Symptoms of Bowel Cancer and some things I don't have such as Blood in my poop. My main Symptoms are the Stomach pains, the Runny poop, the feeling of wanting to be sick and my age. The GP gave me IBS tablets 3 weeks ago and they have had no effect. I might be worrying unduly and there could be another reason for my woes. I hope I get a call saying everything is OK, but am dreading being called back for a Colnoscopy. Thank you for reading this.