5cm and non consistent contractions

I had my 38 week appointment yesterday and they found out I was 3cm dilated (I was 2cm as of two weeks prior) and was having contractions the day before. They hooked me up to the monitor and found i was having long contractions about 12 minutes apart. They were lasting awhile though. I could not really feel them just felt tightness.

They decided to keep me overnight for observation as my waters were bulging and I was up to 5cm at my last exam. It’s been over 12 hours now, no contractions no change. Thinking I might just go home.

I find it sort of alarming that I haven’t experienced much pain and already 5cm. It is my first baby though so I do not know what to expect really. Hospital is about 20 minute drive