Period but not a period ๐Ÿ™†โ€โ™€๏ธ

So I was on BC for full month and then I started spotting just when AF was due. But itโ€™s just spotting for almost two full days. Nothing on pad. Itโ€™s only there when I wipe down. Definitely period like blood. But why absolutely nothing on pad? Should I be worried or is it normal? Never had this earlier.