Lots of boob at this age is still quite normal, so I wouldn't worry about that. They naturally regulate their intake as they eat more - and the rate at which they increase their intake varies a lot baby to baby - but they don't necessarily drop feeds, they just take less at each feed. Breastmilk is still a really great source of nutrition. At this age what they need in addition is iron, zinc,calcium, maybe. They don't necessarily need a large volume.
But, leaving all this aside, the way to know whether she is doing ok is by looking at her. Is she growing, developing, healthy, etc? If so, then whatever you are doing is just right.
You might find it helpful to have a read of Carlos Gonzales' book My child wont eat. (If you're an ABA member you can also watch a podcast of his on the subject).