Irish,
There are a few methods of stabilizing whipped cream, the one using gelatin will hold for a day or two. Using cornstarch, basically adding pudding powder (which is sugar and cornstarch plus flavourings), will hold for a few hours or overnight.
Did you know you can also freeze left over whipped cream? Put dollops on a waxed or parchment paper lined baking sheet and freeze. You will want to use within a week as it will dry out and absorb odours in the freezer. When needed just put the frozen dollop on the dessert and it will quickly thaw.
I hear what you said about DQ. It was many years ago that I got violently ill after eating at McDonalds. I have never been back. I have not eaten DQ treats, except the Mister Misty (freezies) since I was a young child, I always got a tummy ache.
I do not worry about Carrageenan though. It is seaweed and has been used for hundreds of years by peoples around the world as a thickener.