Why am I craving so much salt?

Almost all my life, I've craved things with salt. I put salt on everything, doesn't matter what it is. Because my parents think its so unhealthy, I have little salt packets from drive-throughs that I sneak to dinner. Lately, Ive been craving chicken broth. A couple times I've thrown out the noodles in Raman and just eaten the broth! That and water. I've been drinking at least two water bottles a day, and I never pee. I think maybe it has something to do with my low blood pressure that I've also had my whole life because I am small and thin, but I'm not so sure anymore. I also eat at least 4-5 meals a day- and these are full meals- and over the last two years haven't lost or gained a pound although I have gotten taller. Do you think maybe something's wrong with me?