Ridiculous weight gain

Please don't judge me, I really just want kind words that may point me/my dr in the right direction.
I'm 7wks pregnant and weigh 260lbs according to my bathroom scale. A year ago I was 190 (heavy but not this heavy). I've changed my diet but a week ago I was 250, I take daily walks but I have no idea how to lose all this excess weight, in a healthy way for me and baby. When it gets to a safe point I'm going to have my dr test for hypothyroidism...