I think I know exactly what this is.
Sounds like exposure to BUTYL. and it can be in cleaning products used at home or at her day care.
It may show up earlier for her because she has had more exposures in her life and she is more sensitive to BUTYL
BUTYL causes ME, CFIDS, CFS, FM 'gulf war syndrome'
http://www.valdezlink.com/re/butylcauses.htm
Reaction is IMMEDIATE for me. Usually it is loosening of the sinuses to loosening of the bowels. Ask yourself what is different for you than before this started up. EVEN who is around you differently before, as there can be second hand exposure ... not just direct exposure such as the cleaning products, paints, stains that are used ...
If your Duaghter has still vomitting and diarrhea a visit to the Doctor may be a good thing as she may need some medication. ,if this has eased off make sure you are giving her plenty of fluids to re-Hydrate her. light food.