Severe back pain

I'm 38 weeks and 4 days along and have been having severe back pain for awhile now and it's getting to the point I can barely walk or do anything without it getting worse. Even laying down my back still hurts really bad to where I'm in tears by the end of the day. Not sure if I should contact my doctor or not but it's been getting worse the past few days. As far as contractions go it's nothing consistent.