Child with behavior issues. Embarrassed

My son is 3 and has always showed signs of behavioral issues. Lately it’s been out of control. This past week he had a bad week at school, to the point his teacher asked me if I was thinking about sending him to a developmental school for his behavior. I knew she meant well but I’m so embarrassed. I am currently pregnant with my second child and had a mental break down yesterday because my son was so bad at school and as soon as we got home start with his crap and I just had enough. I legit cried and cried and kept crying. I feel like I’m making a mistake having my second child when I can’t even control my first child. I feel like all I do is yell at my son because no matter how hard I try to gentle parent it does not work.

I don’t understand why he has such bad behavior problems. He doesn’t live in an abusive home, both his parents are together and it’s a healthy relationship. He is loved, lives in a safe home. Gets anything any little boy could want. I just feel like I’m failing him.