my 22 month old feeds at 7pm, 2am, 4am, and 6am. we co-sleep so it doesnt really bother me much. i think at 19 weeks they are still growing SO much and will go throw stages of feeding more often. also every baby is so different, i gave up on the books pretty quickly as i just found that the presure of trying to make DD fit in to the form the books laid out was more stressfull than any issue i was trying to cure! sounds like your doing a great job! good luck.