Back pain.... early labor pain?

Katie

I’m 35 weeks and 6 days tomorrow. I have one loving child. I don’t remember this from that pregnancy. I am 2 1/2 cm dilated 50% thinned and my mucus plug is gone. I have been off from teaching for two weeks. I went back today and after school was over I am having a full back pain that sometimes creeps around to the sides. I took some Tylenol. Has anyone had this before in previous pregnancies? I do see the dr tomorrow after work.