Hi am am also 30 weeks pregnant with the same problem and I went to my OB/GYN and he told me it is perfectly normal to have discharge is small or even heavy amounts around this time in pregnancy
and if you start to have contractions lay on your left side and count for an hour from the start of one to the start of the next and if they are 5 to 10 minutes apart go in. if you are still really concerned it never hurts to go to the nearest birthing center and get evaluated. Never can be to cautious. Hope this helps.