Ok- please help/ encouragement😫😭

Okay so my little boy has been in and around the 45th to 50 percentile ever since he was born but at 2 months he was 12lbs 9 ounces and now at 16 weeks he is only 14 pounds 4 ounces, I breastfeed and I feed him like every 2 hours and he has more than enough pee and poopy diapers. I just want to know if anyone else is experiencing this and what they are doing. I just feel like a terrible mom that he’s not gaining weight 😭