(((HUGS))) What you are going through is very normal. You will loose the weight as long as you stick to what you are supposed to eat and exercise. And for now, yes, walking is good. As you get further out, it gets harder to loose and you will need to up the exercise. You are doing great so far and just keep yourself on track and you will loose.
No matter what you do right now in the first couple of months, you are going to loose. Your body is so used to having so many calories and now you cannot do that as hard as you try so you will loose.
Don't stress. Your doing great.