Sometimes I get the feeling that B&N is messing with me

My latest release sold 13 copies on B&N yesterday... and yet none today so far. How likely is that? Also, how likely is it that it would sell 13 copies in a day and still not have moved up from its #29,000-odd ranking (especially when another book I have sells about ten copies a day and is ranked around #1700)?

Sometimes lately I really feel like B&N has it in for me. Stuff like this just doesn't seem to make any sense...