Upset momma

Mommas and mommas to be I was already a big girl when I found out I was expecting however I know for bigger girls doctors rec. Losing weight I need to lose at least 20 which isn't a lot for me all mainly in my legs and arms what exercises could help me lose and tone legs butt and arms while pregnant and BTW I'm barely eating BC my appetite hasn't increased it stayed the same all I do is eat an extra muffin in the morning but I'm serious about this I need advice and plus I want to have a healthy birth and be energetic with my baby.