She should try not to stress, I found that I could manage my GD with just a small walk ever day and following the diet advice they game me. If I did go out for dinner or indulge in a small treat I just made sure I walked right after or before so that. 4 days may see quick but hopefully they are just trying to help the baby as soon as possible to make sure it's not effected. The first week after being diagnosed was the hardest for me, I think I cried every day for the first week until I realized I could manage it. Good luck.