MammaSue, Nurofen is quite harsh on their little tummy's. I know it is meant to be better than panadol for teething (due to its anti inflamatory properties, but it is best if you can alternate it with panandol.
This may well be why she is a bit windy and constipated. will she eat pureed fruit with yogurt? try pears if she will eat them. This may help her go to the toilet. Panadol and nurofen always back me up.
Also, have you tried putting her to sleep at the first sign of her being tired, ie before she get overtired?
My DS is a nightmare when he is over tired.....