I have a 6 1/2 week old and he does the same thing. As a 3rd time mom, I can tell you that it does get better and this early on you do just have to take it as it comes. Some days my guy will sleep for hours on end and other days he won't sleep at all. Every day is different and your baby will eventually work himself into a nap schedule. He is still very little and is bound to go through some serious growth spurts that will disrupt sleep and eating patterns.
I find working on a night time routine early on helps the rest to fall into place. We started the Bath, breast, bed routine about 2 weeks ago and last night he slept from 8pm until 2am. That is his longest stretch yet!