Don't worry at all! I never leaked or had any sensation that my boobs were making milk when pregnant. After the baby was born she latched well and we started breast feeding. 3 days after she was born I looked like a play boy bunny... My girls were huge!! My milk came in and I'm still breastfeeding my 10 month old daughter!
Your body starts producing colostrum at the beginning of your second trimester. Not all women leak during pregnancy. It's not an indication of how your milk supply will be once baby is here. The delivery of your placenta releases a surge of hormones that triggers your breasts to start producing mature milk. It usually takes 48-72 hours after delivery for that milk to come in. It can take longer if baby is preemie or if you have diabetes or are induced. I wouldn't worry.
You have nothing to worry about. Milk doesn't come in till usually after you give birth anyways. Your breasts will get larger and feel heavy then. I'm pregnant with my third and breastfeed my first two for 13 months each. You might have colostrum come out when you squeeze the nipple but this might not happen till 36+ weeks. So no worries yet :)
You may or may not leak colostrum before birth and the milk can take a week or so to come in after birth. No worries. And ur boobs may not change until after or not much at all.