Braxton hicks or preterm labor?

So I am a FTM 29w2d today, and I have been feeling cramping and tightening in my belly since yesterday. I thought it was just Braxton hicks since they feel like period cramps and are not that intense and are not rhythmic or have been escalating, but now I am nervous. Is it common to experience Braxton hicks quite often during this period of pregnancy? Should I be worried? My OB said to keep monitoring them at home and to rest and hydrate and contact her if something changed (they become rhythmic, intense or have watery/bloody discharge) but still I am quite anxious.