Hello everyone, I'm 19 weeks pregnant and have been seeing my gynecolo…

Hello everyone, I'm 19 weeks pregnant and have been seeing my gynecologist for three days. I haven't gained weight at all during this pregnancy, I've only gained 4 kg in total. I'm worried if that's normal or not. My gynecologist prescribed Yuno mix as additional nutrition. Has anyone experienced something similar? Please let me know if it's normal or not.