Is my heavy cream not actually heavy cream? I am under the impression that the difference between milk and heavy cream is the percentage of butterfat/milkfat. I purchased a gallon of D enriched whole milk today, as well as some heavy "whipping" cream. 

The heavy whipping cream lists Serving Size as 1 Tablespoon, Total Fat at 5g: 8%, Saturated Fat at 3.5g: 17%, and Monounsaturated Fat at 1.5g (with no percentage).

The whole milk lists Serving Size as 1 Cup, Total Fat at 8g: 12%, Saturated Fat at 5g: 25%, and does not list Monounsaturated Fat.

I believe that g = grams.

The Heavy Cream that I purchased is the only heavy cream available at the local store where I generally do my shopping.

So, if heavy cream is supposed to have more milkfat than whole milk (I've read 30-40%, and in some cases higher), why does my "heavy cream" seem to have much lower fat content than whole milk? Is it not heavy cream? Am I missing something? 

Is my grocery store committing dairy fraud? (it's a store brand). If so, is there anything that I can or should do about it (aside from shopping elsewhere)?

I live in the U.S., btw,
You're comparing different quantities. A serving of cream (per your label) is a tablespoon. You're comparing that to 1 cup (or 16 tablespoons) of milk. 

The percentage that you're seeing is not what percentage of your dairy product is fat, but the percentage of the recommended daily amount of that nutrient found in a single serving. % Daily Value is figured using 2000 total calories per person, per day.

From @Jefromi in comments: "And a tablespoon of cream is 15g, so with 5g of fat, that's indeed about 33%, right in the expected range. Similarly the milk is 8g of fat out of about 237g, or 3.4%, what you'd expect for whole milk."