Anyone else? Weight gain!

I’m just about 20 weeks and just found out I’ve gained 20 pounds since I found out I was pregnant!! I was at my lowest weight when I found out I was pregnant and eating low carb and fasting along with excersise. I’m still eating fairly healthy but eating carbs now (whole grains for the most part) and giving into cravings too and have to eat more often of course, but trying to limit my snacks to fruits or veggies. I’ve been walking regularly. I think my body’s kind of in shock from the change in diet so I gained weight back fast. Is this too much weight gain?? Or is this normal??