Contractions

Hello ladies! I am 39 weeks and I have been having pretty consistent contractions. Experienced mommies, is it safe to say that I will know when it's time to go in as far as pain? I still in a managable amount of pain. I'd say maybe a 4 on a scale of 1-10, but my contractions are coming 2-5 minutes apart. I only live 20 minutes away from the hospital. Is it safe for me to lay down and wait to see if they are the real deal? They feel like period cramps right now. I haven't slept much and have been having these contractions since 1pm