I am totally with you and appreciate what you wrote because I have been having a similar problem. I definitely don't feel confident as my 4week old wants to nurse constantly that even my husband doesn't get much time to hold her because she gets whiny with him.
I am also taking fenugreek, lactation blend pills from Gaia and Domperidone which I believe has upped my milk supply but I had to start my LO one formula also because after week 3 she hadn't gotten up to her birth weight. Now, I've decreased her formula because I swear that I have more milk, but also don't know if she is gaining as I won't be weighing her till our 2 month check up. She definitely sleeps at night (thank god). We cosleep so every three-four hours we wake, she eats and we go back to sleep.
Anyway, I know that everytime she is on the boob she isn't always eating (but isn't that supposed to help my supply anyway?)
I feel like I'm doing the right thing but without a scale I guess I'm not sure.