11 weeks and severe back pain! Normal??

Caroline • engaged to the love of my life. We've been together for 10 years, baby number #1 on the way, due 25th August 2016 ❣❣❣
Hi I'm 11 weeks pregnant and for the last two weeks I have had severe lower back pain, my midwife told me it was normal but I'm starting to worry cos it's only getting worse to the point I can't move, walk properly and when I lie on my back in bed its agony. I have an electric wrap that I wrap round me to ease the pain, it helps but not by much. I work in a children's nursery so I am constantly up and down on the floor, I'm active all day and I'm bending over tables looking down at kids work etc, my colleagues are helping out best they can but I can't let them do all the work, by the time I get home I am in agony!! Any tips to help ease the pain and has anyone else experienced such awful back pain so early on in their pregnancy?? Thanks for reading