Any time you get a PS you're not sure about, it's important to stall. By feeding him, his next test is probably going to be higher....but we'll have no way to know if his numbers went up because of the food or went up because the last shot was starting to wear off.
Do you have everything you need in the way of supplies like strips, HC food, Karo/honey/syrup?
Are you able to test as often and as long as necessary tonight?