All of my villagers are weakened because I turned the game off for awhile and my farmer decided to research instead of farm! ugh! Anyway 3 of my villagers died and the rest are weak. They are not getting healthier no matter what I try. Is there a stew that can make them healthier?

There is. And you should mark the Tiltle of this as a Spoiler.

Purple Flower+Purple Flower+Orange Blossom.

ok I will mark it...I had already tried that combination and it just makes my villagers jumpy. Is there a certain level I need to be on in order for it to work?

You're probably using the wrong flower, since it can be hard to figure out from people's color descriptions exactly which herb they are referring to. There is a complete (spoiler) list of all stews here in the VV2 Guides.

Here is a pic of all the VV2 herbs: (it's a SPOILER) VV2 herbs
The 3 you need are (Highlight for spoiler) 2 Purple Cosmos on the north and 1 Orange Bromeliade on the south (end of spoiler)
Good luck!