Insecure about my boobs 😩

So I’ve never had huge boobs, but they fit my body. Now that I’m starting to get a little thicker every where, my boobs aren’t... they literally seem to be shrinking?? I’ve never wanted plastic surgery, but I’m highly considering it more than EVER now. I went from a 34D to a 34C and now my boobs don’t even fit in my new bra I haven’t even had a month... why is this happening, has anyone ever experienced this?