Breastfeeding a newborn

My LO is a week old today. breastfeeding has been so much harder than I thought. All the women and friends I've been around have all had babies who instantly latch. My LO latched for the first time with a breast shield at 5 days and is still BF with a shield. Occasionally he will latch with out one but is pretty picky.  It makes me so nervous now that we aren't using a bottle. I have no way of knowing if he's getting enough. My LO will BF for 10-15 minutes fall asleep than wake up anywhere from 30-1hr later to eat again. Than once a day usually in the evening he will sleep for 1 2-3hr time period.  Any advice , words of wisdom or encouragement? I just feel like I'm doing something wrong. I always thought that he would feed longer and take a few 2-3 Hr naps.