Can't gain weight

ami
I'm 14wks pregnant.  
I eat like 3 breakfasts, I feel like I'm eating all the time, I eat late, eat cereal before bed, eat in the middle of the night cuz I wake up starving & eat first thing in the morning.  I thought I would gain for sure because of Thanksgiving this past week too!  
I'm the same weight today that I was when I took BFP at 4wks.  I doesn't make sense to me because my boobs are huge, baby's the size of a lemon, my belly is bigger than before... 
Should I try harder to gain weight?  or just chill?  (5'-10" 173lbs)   Anyone else feel this way?