Weight gain??

I'm 26 weeks and 4 days pregnant and I was just curious if my weight gain is normal i weighed 125 at my first appt and I'm 5'7 so according to my doctor I was underweight and she wanted me to gain 30 lbs throughout my pregnancy, but today at my appt i weighed 164 so that's almost 40 lbs already..my doctor didn't seemed to concerned at my appt today,but I was just curious to know if anyone else has gained this much this soon or if I'm just fat,I feel so bad and hate looking in the mirror...