It is completely normal to began leaking near your third trimester. It is not milk you are leaking though. It is colostrum or premilk as some refer to it. It has antibodies to help protect your newborn from infections and viruses until your milk comes in, which may be a few days after you deliver.
I brought breast pads when I began leaking colostrum near the end of my pregnancy (around 7 months). However, I disliked them because the annoying things kept sliding and would not stay in place, thus leaving milk-like stains on my bras. My friend suggested pantie liners. They are thin, hold in place, and are absorbent while comfortable. I started using those instead and prefer them now over the bulky pads. I also used them afterwards until my breasts dried up.