Sickle Cell Trait

I have sickl cell trait. I have been mildy anemic for most of my life.
My primary told me that SC trait can't cause any symptoms and is convinced that I have a bleeding ulcer despite no symptoms and a lenghty history of anemia.
I saw a gastro who said that trait can cause smaller red blood cells which is consistent with my test results (enough red blood cells but small and pale).
It seems to me that if you have smaller cells then they can't asbosrb as much iron and thus a slight anemia is possible.
Additionally I have read that there is increasing research that shows that individuals with SC trait are at higher risk for sudden death when engaged in extreme physical activity (like Marines in basic training) and should be cautious when mountain climbing at high altitudes or scub diving and when having surgey etc. This seems to indicate to me that something isn't quite right for those with SC trait and it seems to be connected to the oxygen transport mechanism?!
So who is right, are all SC trait carriers symptom free with no phsyiological changes or is there an increased rate of slightly smaller red blood cells thus, perhaps, some anemia and oxygen transport issues?