This is a really exciting time for you. Enjoy it. It's a nice time of year to get out with your baby. Just put the baby in the stroller and get out walking as much as you can. Don't over do it, but even a ten minute walk will be good and try to do that a couple of times a day. Also, no fast foods. I find that I'll eat when I'm bored, so now I drink water. Also in the afternoons when I'm tired or bored, I'll munch celery. I get the sticks from Costco and I eat one or two every afternoon. They are thirst quenching and filling and add no calories to your diet but are rich in vitamins. No salt.
All the best,
Stephen