You are not over reacting but be careful not to give this too much attention (easier said than done) as she might start to enjoy it.
I childmind and I look after a little girl who won't eat, her mother is at her wits end (me too sometimes, it's so worrying and frustrating) She often complains of a tummy ache, her mum took her to the doctors, same thing, she's active, don't worry.
She will eat any amount of biscuits and sweets though so I definitely never offer them.
I just sit her down at the table with the others to eat the same as them. (I made the mistake of giving her the choice of food for a week, we all had spaghetti on toast for 5 days!!! and she still wouldn't eat it) She did try brocolli the other day and liked it (success). Most of the foods she tells me that she doesn't like she has never even seen before, let alone tried them so I do a deal, try it first and if you still don't like it then you can leave it. She is not as bad, but there is still room for improvement, but try not to give her the same thing all the time, we tend to serve some things if they like them day after day and they grow tired of them then. Keep serving different foods and even if she says she doesn't like them, try again a bit later. Even if she doesn't eat them, she will eventually when they become familiar to her and she realises that there is nothing else.
Hope that you will be able to persevere, its so hard but hang in there.
I would also have another chat to your health visitor about the tiredness and crying, just to be sure.
