nausea and diahhrea?

36+1 and last night I woke up with the most awful stomach cramps (not contractions, this is my second so I know it wasn't that) and nausea. Had diahrea and still felt a bit nauseated after. Better this morning, so far. Heard this could be a sign that labor is soon to come, but never had this with my first. Anyone else have anything similar?