Should I worry?!

Went for my glucose test today, I am 26.1 weeks. And doctor informed me that he thinks my umbilical cord is too low so I will have another ultrasound in 4 weeks to check on that and see how she is growing.... he said he cant tell from my last ultrasound if it's too low or not, but he thinks it may be. I'm officially worrying now and super anxious.

My last pregnancy my water broke at 35 weeks and I had her at 36 weeks.

I started progesterone at 16 weeks with this pregnancy.

Everything has been normal besides my blood pressure being low but that's normal for me.