Weight gain. . . Should I be worried?

The other day I went to the doctor and was told that since I'm considered "obese" due to my height and weight. I am not to gain more than 15-20 pounds by the end of my pregnancy.

I'm trying not to stress so much about it because stress has contributed to some of my weight gain in the past but I also want to make sure to be healthy for my baby and myself.

I need some pointers. . I don't have big meals throughout day because I'm always so busy at work I just eat small lunch (only have 30 min) and graze throughout my shift.