So this was something I never thought I'd be doing! After building up some confidence and arranging a fairly secure hiding spot for them, I went out and bought girls' Goodnites, since they would probably have the best chance of fitting me (and they actually ended up fitting surprisingly well!). I made sure to make use of the window of time I had between me getting home from class, and anyone else getting home.
I was pretty nervous when doing it, but I put it all aside and went straight for it. A few things helped calm me down through the experience, the first being that I knew exactly where to find them as to make the trip as quick as possible. Also, the store luckily had a self-checkout station, which I made use of.
Before I knew it, I was in and out of the store in a matter of minutes. Feels good to have gotten it over with, and to finally have my first pack. I can only hope it gets easier the next time around!