go and get yourself checked out right away
Well... I definitely would call my doctor and let them know what happened and the symptoms your experiencing. It's normal in pregnancy to have an abundance of discharge which could be the cause of the wet panties. The baby is very protected in there this early so I wouldn't be so worried about hurting the baby but the concern is the higher risk of miscarriage. Why were you a threatened miscarriage last week? Call your doctor and tell them what happened and see if they will let you come in to hear the heartbeat, that will put your mind at ease. Of course if you have any bleeding at all, call your doctor immediately.
You need to see your doctor. Are you getting prenatal care?
I THINK YOU SHOULD GO TO THE E.R IT SOUNDS SERIOUS........