Am I allowed to trademark the name of my business even if it's the name of someone else's product?
The Trademark Office is concerned with marks that are the same OR similar to those already registered and that are being used in the same or a similar way. You're trying to establish a mark that's nearly identical to one that's already in use, and to use it for a nearly identical business.
What happens indirectly is that you would be trading off of the goodwill and hard work that the Oatmeal Fudgie Wudgie company has put into its product and branding.
Choose another name.