When to go in

I’m due w Baby # 2 I was induced w my first, & have an induction scheduled on Tuesday w this one. I keep getting a tight belly & it’s uncomfortable kinda like period cramps. I have sharp pains I’m my back & yesterday when I was checked she said I was 3cm dilated & she could feel her head. We live over an hour and a half away from the hospital so how do you know when to go to l&d? I’m 39 weeks 3 days