The constant feeding could be a growth spurt Surprise, there is one at 6 weeks and they can last up to a week.
I would seriously ditch the scales if you really want to try going without top-ups because they will just cause more stress and, unless you're weighing before and after every feed, you might only be measuring baby's 'snacks'.
Like Feronia said, the best thing you can do (if you can) is room in, have a couple of days in bed or on the sofa, skin to skin and just feed, feed, feed. Keep an eye on diaper output as that's a much better guide to how feeding is going along with weight gain of 5oz or more per week (try not to weigh more often than that) - if your baby gains more than that then you can rest assured you have full supply.
Maybe give it a week or two and if you're still not happy then reintroduce the top-ups if that's what you want. You can do this though!