21 Weeks + 5 Days... How's my bump?

Hey ladies! So this is my first pregnancy to this point (miscarriage at 9 weeks last November) and I don't feel like my bump is that big yet. It's growing, don't get me wrong. I have a doppler to hear my little man's heart beat ♥ every day and our anatomy scan was right on target. Is it normal to worry that I'm not big enough?! I always exercised regularly before getting pregnant (weights, pilates, yoga, cardio) about 6 days a week and I'm 5'8" tall. I've read that both of these factors can affect the size of a bump. What do you ladies think?! This pic is from Father's Day this past Sunday.