What are false contractions like?

Im halfway through my second trimester and this morning I woke up to a small amount of hip pain that quickly went away. So I adjusted my self and went to go back to sleep and got what felt like a cramp in my back and all through my hips and stomach. It went away after a minute or so but it wasn't like a cramp I've ever had. My stomach tightened slightly and everything. (No bleeding either) I've only had one so far and it hasn't happened again but is this false contractions? Im at high risk for preterm labour also. But I feel like it would've been more consistent and I think I'm too early.