im 35 weeks this week, and i have started craving anything with sodium.

at about this time with my DS for the last 3 weeks or so i just needed powerade drinks and salty stuff. and now this pregancy i have started craving it again.....?
maybe my body gets low around this mark of my pregnancies?
i also cant get enough soda water?
can anyone tellme if this is my bodies way of telling me something? and being only 3/4 weeks to go having a c section on the 21st Feb can i just drink soda water?
its pretty weird maybe bub is talking everthing i have........
would love to hear your thoughts.....thanks in advance TG