Concerned about weight gain!!😖

So before I was pregnant I weighted 117lbs then in the beginning of my pregnancy I was so sick I got down to 104lbs now I'm 30 weeks and weight 128lbs I wasn't concerned about my weight gain at all until I went to the doctor yesterday and she made a big deal about the fact I gained 4 pounds in the last 4 weeks, then she looked at my belly and said oh your skin is stretching nicely but if you keep gaining 4 pounds every 4 weeks your going to get strechmarks then right before she left she told me I was only allowed to gain 1 more pound until my next visit which is in 2 weeks now I'm scared I'm gaining to much weight and I really dont over eat or anything ugh someone give me some advice 😓