They change so rapidly......as soon as you think you have them sussed, they change their routine!!
At five weeks, I'd be expecting a growth spurt which in my case lasted right thorough to over four months with 2 hourly feeding round the clock with my second.

The tugging could suggest trying to get another let down or to try and make your milk come out quicker and feeding more often would back that up. Your baby is trying to increase your supply and by being given complete access all the time, is the perfect way of doing it.