I checked the Ohio laws regarding vehicle purchases, and Ohio laws in general.
The laws providing a three day right of "rescission" apply to entertainment contracts (television-phone service) and "home sales"- that is purchases one makes at their home from a salesperson who has solicited the sale at their home.
There is no right of rescission for a vehicle sale. There are many regulations concerning vehicles which are defective and vehicle warranties. Lemon Law type regulations. However, that is, apparently, is not the case here.
There are laws against unfair and deceptive practices in sales in general. If you were "bullied" into purchasing the vehicle, and if the representations of the salesperson were not true, you might have a right to "rescind"- that is reverse- the sale.
However, in general one cannot reverse a vehicle sale because of a change of mind.
Since the sale was so recent, there is a good possibility they haven't processed the paper work, as yet. You should contact the dealer ASAP and ask them if you can return the SUV and purchase a truck...you would, of course, have to purchase the truck from that dealer. They may very well allow you to do this, as dealers in this economic climate are catering to their customers.
If you were coerced in any manner into purchasing the SUV, this will give you more leverage in dealing with the dealer.
Also, you should look very carefully at the financing contract. Maybe the lender allows a right to rescind the sale. This is not the norm, though.
Hope this helps. Wish the news was better, though.