Tips on how to baby and I become healthy

Hello I'm 18 weeks pregnant but my tummy is Hindi masyadong lumalaki.? Is that normal? Can you give some tips and advice. This is my first babym I'm already 25 yes old. What food and veggies do I need to eat in order for me become healthy and also the baby. #1stimemom Please help me? And share with me your experience. Thank you and God bless