Contractions start off usually like light period cramps and become more painful over time
the pressure feeling you have is with baby just dropped or babys putting pressure on you back side or your in labor....
Go get cheked out, I felt like I needed to crap when pushing my daughter out, ligament usually feels like a light pain/cramping pulling sensation but I dont remeber having it after 35 wks....
Wish you luck keep us updated
jess