Eating real food is the best you can do for your baby. But it will be difficult for you: pregnancy is a big change for your body + switching over to new way of eating. Maybe at least one thing do slowly. And the one you can do at your pace is the PB. I started gradually and did not have any "carb flu", just after some time realized that my tasty oatmeal is not tasty any more and that my cookie with afternoon coffee tastes good but gives me stomach pain, etc. The same with my daughter - she did not like eggs, very little bacon, now its her favourite. Tastes change.