Does anyone know about building muscle at the gym?

I have been doing upper body weight workouts for about a year now and specifically for about four months doing them three days a week and I've noticed I've gotten a lot stronger because I can lift weights that are definitely heavier than I used to be able to but my muscles don't look like they're getting any bigger.

I don't necessarily eat the healthiest however I have been using protein shakes and trying to eat more stir-fries and vegetables and fruit trying to stay away from having bread as often and having less pasta end I refrain from eating desserts a lot of the time.

People also suggest eating a lot of carbs and gaining a bit of weight will help with the building the muscles which is strange to me however I don't need to do that I have been out of high school for about five and a half years when I was in high school I weighed 132 lb and within the five and a half years 1 1/2 of those years I gained 20 lb and then recently for the holiday season for Thanksgiving and Christmas before that I weigh 270 lb and now come January I weigh 180 lb so I think I'm adding weight fast enough I would love to lose weight by 140 or 150 lb again and then gain the weight back just by adding muscle

I was wondering if anyone knew if it was genetics my dad's side of the family you generally are bigger and have somewhat week 2 medium sized muscles but on my mom's side it's different and I think I got more my mom's side of the family only one uncle on my mom's side of the family has decent size and muscles I'm thinking it will just take me twice as long to get the muscles to the size I want compared to most people because of my genetics of muscle mass and different things but I wanted someone's opinion