L.R.
She may be undergoing a growth spurt and needing more to eat. That is normal and not something you can control; you can only get through it with her and give her what she needs when she needs it.
Or she may have been taking in less, at each breast feeding during the day and early evening, than you realized. With bottles at night you can tell exactly how much baby is eating but on the breast you can't always tell even if you "feel" the baby's had enough or the baby seems to be done; some babies just tire out before they really are satiated, (which can be another sign of a growth spurt -- getting tired) and that means they want another feeding sooner. Not a lot you can do about that one either, unfortunately.
Did the doctor ask about symptoms of acid reflux or other issues that could cause her to wake? If you don't think it's food she wants or something wrong with her physically, check her sleeping clothes and crib for anything that could be irritating her or waking her.
If so, and there's nothing going on, a growth spurt or a tendency to need smaller feedings may be the case. And I know you don't want to hear this but....some babies, like some kids, like some adults, just do not sleep long periods without waking. The "babies who sleep all night long every night" seem to exist according to some parents but it's not the case for all babies. My daughter is 10 and still changes her sleep habits periodically -- wakeful for some months, solid sleeper for a while, restlessly iin between for another little while. It's not a matter of discipline or wilfullness; it's just metabolism and, well, her nature. I'm an extremely light sleeper who never sleeps all the way through any night. Babies are individuals too. But that's pretty hard on the parents, I know.
Good for you for staying up with her when she cried. Please do the same when it happens again. You may get posts on here saying, "Train her, discipline her, don't cave in, let her cry it out alone," etc. but I am on your side: An infant this young can't manipulate adults, she doesn't have the mental ability to do that for a very long time yet, so she does need to know that her most trusted adults will be there if she is upset. When you leave a room, in her mind you are vanishing forever and ever; she has no concept yet that you still exist somewhere else, so your presence is vital to making her feel safe as she goes through whatever she's going through.