Help? Brown watery discharge

Im 38 weeks and 3 days. Okay so at about 4:30 this morning I got up to go to the restroom and when I whipped there was a semi-bloody and brown mucus string. (Only a very tiny bit) so I figured okay my mucus plug is starting to come out! Well since then I've been having a brown watery discharge and no more mucus. What exactly could this be? I'd call my ob but I always get a machine. I'm a ftm so I'm pretty clueless on everything. Thank you to everyone who can help! Just trying to make sure it's normal or if I need to go get checked out. Oh and I forgot to mention I did have a membrane sweep done yesterday around 3 in the afternoon. Also the discharge isn't running down my leg or anything it's spots here and there....