First of all a big Congratulations for the baby!!
It is very hard to give a solution based on the information provided by you. You need to understand the changes in your body post pregnancy and take up a food plan accordingly. It is very common to gain weight post pregnancy. The key is to understand your body requirement and lifestyle and couple it with some freehand exercises to get rid of the target fat.
I would suggest you to visit a good dietician and explain to her your present food habits and allergies. It is required to get your anthropometric measurement done to get a detailed personalized diet plan.
Randomly following a dietplan is not advisable as it might or might not suit your body.
Live healthy and enjoy every bit of these precious moments of motherhood!!
Have a nice day!