Don't worry. Breast milk doesn't come in until a few days after the birth (before that it's colostrum - with my first baby there was no sign of that either until my son was born).
Incidentally, the milk is actually made in ducts under your armpits, not in your boobs, so breast size is no indication at all of how much milk your body can make. I'm small chested (34a) and had no problems at all.
You really won't know.til baby is born. If you are concerned I would go ahead a talk to a lactation consultant now and plan, if you need to schedule a weighted feed after baby is born. That is the only way to truly see how much baby gets. You are still early and of you breastfed your first without problems you will likely be fine.
Don't worry the milk will come..often not until after birth!
My boobs started swelling in the second trimester.
You might be a late bloomer. Some peoples breast don't actually grow.
Are you leaking at all?
If not, I would consult your midwife.