Not gaining weight

Jennifer
Hey out there... Has anyone experienced lack of weight gain? I'm week 10 exactly and have increased my calorie intake by 100-200 a day as recommended, but haven't gained any weight yet. In fact I lost a pound. 
Is this happening to anyone? My breasts are no longer sore and my morning sickness was always mild but is now virtually gone. 
Should I be worried I haven't gained weight?