Hi, Rylie. I'm a FtM, but also a student nurse who has an interest in being a surgical nurse, so your post caught my eye. To achieve the appearance of a full female breast that's appropriate for most MtF chestwalls, you'll need an implant of 300cc or more.
When you had your operation, it was probably glandular tissue the doc primarily removed. Even if you would have kept those, there are biological processes that keep them from looking like the healthy female breasts you desire. You likely won't experience significant breast growth, but that wasn't really going to happen. Even for women's clothing, you need a considerable bust that MtF's simply are going to lack, even with optimal tissue development from HRT. The idea that you've lost significant female breasts just isn't true.