What if I gained 10 pounds during my 30 week of pregnancy. Is it ok? What kind of food shoulf I eat to lose a little bit of weight?

That is too much. Discuss with your OB , your OB can refer u to a pregnancy dietician, and u need to cut down on the carbs and salt , and eat higher protein, esp at night for dinner at the max wt gain should be 4 pounds in 4 weeks.