Just ring the Maternity Ward and ask them. They will probably want you to come in for monitoring.
With my ds2 my waters broke early in the morning, so I went in to be checked out and they told me I was having contractions but I couldn't feel them at all. I was sent home and I had stronger and stronger Braxton Hick's throughout the day (like you are decribing) and I kept thinking "is that a contraction?" All I can say is when the first real contraction hit, at 2am the following morning, there was absolutely no mistaking it - I remeber sitting up in bed and thinking "ah yes, NOW I remember what it feels like!"
But you may be starting off so do please ring the hospital. Good luck, hon, thining of you xx