Personally I would go to a dietician or paediatrician for help.

When Matilda had iron issues she had the dark circles under her eyes. She wasn't lethargic, but pretty darn cranky (really, when isn't she?) I used multivitamens and In-Liven. I would put it in chocolate rice milk because it was the only way I could get it in. I gave both multi and in-Liven for 3 months and saw a huge improvement.