Hello, Thanks for writing to HealthCareMagic, I am Dr Muhammd Ahmad, I have closely read your question and I understand your concerns, I will hereby guide you regarding your health related problem. Yes these two are complications of uncontrolled diabetes if blood sugars stay uncontrolled for a long time. Diarrhea immediately after meals is called dumping synderom it can be controlled by some medications and eating smaller multiple meals over a day instead of larger meals. Dizziness can be due to sugar fluctuations as your doctor suggested the best way to deal with this is to check your sugar levels when you have this problem and keep a sugar monitoring chart to help your doctor. Take one reading in morning during fasting one reading when younfeel dizziness and one ready before dinner. I hope this answered your question, if you have more feel free to ask,otherwise close the discussion and rate it. Regards. Dr.Muhammad Ahmad. General and Family Physician..