BABY DEVELOPMENT

my soon to be 16 month old is yet to be talking. i call his bottle “babas” and he seems to be saying that, and sometimes i feel like i can hear him say “ball” but he just babbles all day. he doesn’t say mama, he doesn’t clap, or point at anything. he barely acknowledges his name and he does get upset when i say “no”. sometimes i feel like he can understand but sometimes i feel like he doesn’t. he doesn’t like to interact with me as much as i would like, example: he’ll throw the blocks when i try to stack them for him to see, he will smack the books i try to read him, he doesn’t throw the ball back to me no matter how much i try to teach him. he’s peds said it was normal but when i took him to another doctor he said my child was severely developmentally delayed. he referred me to early intervention, speech and physical therapy. he was approved for speech, he may not be approved for PT because physically he is doing a lot like climbing, squatting and getting up, ofc walking and he’s clearly going to run soon. idk what else to do, i do feel like ive failed him but idk how to get him to interact with me more. im trying to get out of the “baby voice” but its honestly harder then i thought lol. does anyone have any advice?