When I was in hospital the other week they did a CTG as I was getting the same thing but they did say to me that it is completely normal especially with multiple pregnancies as we have twice the amount of baby in there so our bodies are feeling more IYKWIM. Wouldnt hurt to talk to your midwife/OB though if you want to check up on things before friday because I never had a show with any of my babies and my waters didn't break naturally with Claire either despite being 6cm dialted by the time i got to hospital.
We started the fortnightly CTG monitoring 4 weeks ago and I have a tip for you get them to set it up with you lying slightly on your side, they try doing it on your back but the extra weight from twins will restrict your blood flow and make you feel sick and dizzy and just YUCK!