I've done some posts previously on vitamin C - I can't work out why a supplement of this could hurt you, as long as you DON'T get a citrus type.
Not sure about the iron and C as I'm D.
All dark green veg are high in iron, so broccoli, spinach, etc. As you're C, can you cope with more of these? Maybe making some soup would be an idea - that way you could puree the veg to minimise the insoluble fibre.