Sugar in both ingredients and a light can't-taste-the-booze taste? Yup -- high calories and lots of consumption.
Try switching to something with less (or no) sugar and stronger taste, so that you drink it more slowly. A nice single malt scotch neat would be perfect.
It's not uncommon for my wife to ask for "something that's not too good" so that she will savor it. Unfortunately her tastes are broadening about as fast as I can come up with good challenging drinks. She now like bourbon drinks. I'm still pretty save with anything from the isle of Islay. An more than about 1/2 oz of Fernet will slow her down. Man, this is fun!