Weight gain

I understand everyone is different, but I read a lot on here people losing weight during the first trimester. I've read you're not supposed to gain any, but how realistic is that?!? I'm constantly nauseous, and to prevent puking, I have to eat almost hourly. Since I have horrid food aversions, the only thing I can stomach is carbs. Literally all liquids make me ill, so I can barely choke down 20oz of liquid a day. I feel like I'm the only one gaining weight on here! How much is avg to gain during the first 12 weeks?! I'm freaking out...