Yep. Yep. Yep. What pp's said!
You honestly watch your baby to make sure they're getting enough. You look for
1) plenty of wet nappies (check)
2) appropriate weight gain (check)
3) contentment after feeds (check)
I second Woopster's pump advice. It really doesn't tell you anything except whether you respond to a pump or not.
Baby is much more efficient. So don't look to it to tell you about how much she is getting. Also, know that around 3-4 months (give or take a couple of weeks) your boobs get a whole lot more efficient themselves. They know how much milk your lo needs, so they usually stop producing an over-abundance. That is NOT your supply going away. It is *normal.* Repeat with me: NORMAL.
Just wanted you to be ready for it so you're not surprised if pumping goes down a bit. Continue to look at the 3 things above to make sure lo is still getting enough.
{{hugs}} You're doing fine, hun.