Consistent period cramps in back

So, I only labored with my son (27 freaking hours) only to have a c section. All of my contractions were in my back, I never felt any thing in my stomach...similar to my period cramps only ever being in my back. I had a scheduled c section with my daughter, never had so much as a Braxton Hicks contractions with her. I have had loads of Braxton Hicks this time. Now, I'm having period like cramps in my back and they freaking hurt like a mofo. My stomach isn't getting hard, and I can't really time them because they are consistent, no end. Should I be worried? Is this normal? I am drinking tons of water....I'm 37+1 and c section scheduled for 5/19...I don't think they are contractions but I don't really know