Blurred vision and your GP is not bothered? I had blurred vision when my bg was high. Is there something sneaking into your diet that is pushing up your bg? I was happily drinking 'no sugar added' squash recently and was getting 11s in the morning. Finally realised what was going wrong, cut out the squash and my bgs are down in the 8s now. You have my sympathy with the gastro problems. Pretty sensitive to medication myself. Perhaps if you posted a list of what you have eaten on the average day, people can advise?
I would get on the phone to the GP again though. That is a dreadful attitude.
P