Scary rapid weight gain !!!

Hi ladies I'm kind if in shock . I had my weight and BMI done at my 12 week scan at the start of the week . And I'm so surprised to learn I went from 110lbs to 125lbs !! I knew I had a bump much sooner than a lot of moms to be and taught because I'm so short it just showed sooner . I'm 4'11

The worst part is I spent all of the first trimester being horribly sick so how on earth did this happen . The midwife didn't bat an eye at my weight but I'm worried . I had been drinking lots of sprite and juice as it was all I could stomach and eating ice pops and toast all things I wouldn't normally eat .

I totally gave up my work out routine but I plan to go back to it in the new year as I'm starting to feel a bit better . Has anybody else had this happen does the weight gain slow down .This is my first baby .

I'm so freaked out. Any advice and tips are welcome .