slip and fall liability in MA

i slipped and fell on a puddle of water in the bathroom of the big y. i have 2 hairline fractures in my shoulder and one in my hip. after the suits arrived i heard one say that they see the water and instructed an employee to go get the camera. there was a caution wet floor sign under the sink and not near the water, infact i didnt even notice it until i was on the floor. there was also another shopper in the stall next to me before and while i was in the bathroom. do i have to prove that the store had been previously informed of the water on the floor or is it enough that because there was no notice that the floor was wet that it was reasonable for me to assume the floor was dry. and that the store is negligent