I'm sorry you are having trouble with your iron levels. I have had lifelong anemia issues & require supplementation, so I know how it feels when iron levels get low.
It is not silly to hope for your hair not to become thin!
I hope you have good results from cutting out grains in your diet. There are plenty of delicious foods to eat that don't require grain.
ETA: Regarding Vitamin C, can you eat strawberries? They have a good amount of Vitamin C, I think.
My hair on October 26, 2012.
History: After major shedding I cut from knee to tailbone. After continued shedding I cut from tailbone to BSL. My hair grew to waist length and I cut it back again to BSL, hoping for the length to thicken a little with the regrowth. It never got better, only worse and eventually developed severe scalp issues. Went to buzz cut, then micropixie for several months while scalp healed and growth returned to a noticeable rate.
Goal: Grow it long again.
Oils: Virgin Coconut Oil, rarely other oils.
Wash: After sweaty workouts, or when dirty.
Seamless plastic comb for detangling.
I put up simple videos on YouTube (but my hair underwent MAJOR shedding in 2010 and looks thinner now, I'm embarrassed to wear it down now). My channel:http://www.youtube.com/user/HairyKnees1?feature=mhum
My Hair Blog/Journal:http://flowinglonghair.blogspot.com/