More discharge than normal

I am currently 31 weeks and I went to the Emergency Room last night due to light pink vaginal discharge. They did a NST, and checked my cervix. Turns out I'm 1 cm dilated. They said I started bleeding while checking my cervix. So that's probably where most of the brown blood came from. But after I went to the bathroom and wiped I see discharge on the toilet paper. Could this be part of my mucous plug? I know you can lose some of it and it'll regenerate itself. I was also told baby is small for gestational age and we would have her at 37 weeks.