Dilating??

Alexa

I'm 31 weeks 4 days and found out 2 days ago I'm dilated 2cm and I'm 50% thinned. I've been on contraction medicine since 22 weeks but baby boy has been head down since about 26 weeks. Should I be worried that I'm already dilated 2cm?! I had an appointment last Tuesday and I wasnt dilated yet. I go back to my doctor today at noon to see if anything has changed. I've dilated fast already so I'm worried...