Pregnancy 2.0 Weight Gain

For a couple of months I was concerned that my weight gain was out of control with this pregnancy.  With Evelina, I gained gradually week to week, but this time around I noticed I was gaining in huge jumps...10 lbs in a month....eek!! Most likely it was due to my eating habits and gestational diabetes (GD).  Since being diagnoses with GD I haven't gained more than ½ lb.  Naturally, I was a little concerned at my last appointment, but the Endocrinologist said that Siby is still gaining weight.  Hopefully he is correct.   We will find out the approximate size of Siby at our 37 week u/s scheduled in a few weeks.  

Pregnancy Weight Gain - Evelina 
From 0-16 weeks: Up 3 lbs
From 16-21 weeks: Up 7 lbs
From 21-25 weeks: Up 3 lbs
From 25-29 weeks: Up 5 lbs
From 29-31 weeks: Up 1 ½ lbs
From 31-33 weeks: Up 1 lbs
From 33-35 weeks: Up 2 ¾ lbs
From 35-36 weeks: Up 1 ¼ lbs
From 36-37 weeks: Up 1 ½ lbs
Total weight gain = 26 lbs 

Pregnancy Weight Gain - Siby 
From 0-16 weeks: Up 3 ½ lbs 
From 16-20 weeks: Up 2 lbs 
From 21-24 weeks: Up 9 lbs  – What did I eat?? 
From 25-28 weeks: No change 
From 29-30 weeks: Up 10 lbs  – Again, what happened?? 
From 31-32 weeks: Down ½ lb  – Changed diet due to diagnoses with GD 
From 33-34 weeks: Up ½ lb 
From 35-36 weeks: TBD
Total weight gain so far = 24 ½ lbs 

How is it that I look and feel so much bigger though?!?