Labor or just a tease?

m.m.manni@gmail.com
I'm 38.4 weeks and for the past hour have been having fairly regular contractions with mild cramps. I just generally feel unwell, slight nausea and vaginal pressure. I haven't lost my plug and no water break. Thing is I'm at work, an ER nurse and I work over night... I don't want to leave my fellow staff short if baby girl is just practicing. Thoughts....?