Last night in the middle of the night I woke up with severe cramps lasting about five minutes, and they were about five mintues apart, but it only happened a few times in a row. I had nausea and a lower back ache too. I woke up this morning feeling fine so I didn't call the doctor. But now I've been having a lot of braxton hicks throughout the day, is this normal or should I call? I'm 24 weeks.