Thanks for all the responses everyone!
I tried it with just heavy cream and Truvia yesterday morning, and it was definitely hard to get used to. The cream doesn't seem to cut the bitterness of the coffee as much as creamer, but I'm assuming that it's because it's not nearly as sweet. I tried again this morning, but this time I added a small splash of vanilla Torani Sugar Free coffee syrup (totally forgot I had it!), and it was a lot more doable. Definitely something I can get used to.