Count your calories. First trimester 1800. Second increase by about 200 and same with your third . Yes your going to be eating more calories but it does not mean that they have to be bad calories. Ex: yogurt and a healthy protein source granola bar: this adds up to an extra 300 throughout the day :)
Watch your sugar. Realize you will gain weight and accept that. Eat small and frequently. And yea. Eat healthy :)