Depressed Mother

I’m a mom of a beautiful 3 year old boy. Over the past year and a half my husband and I noticed his cognitive development was not up to par. He wasn’t talking or using joint attention. I have enrolled him in early intervention and once he graduated from that I put him in speech and occupational therapy. My son now knows well over 250 words . He knows his shapes, alphabet, numbers, colors etc. He can even spell his first and last name. The problem is he won’t show others what he knows and he has an issue with communication. I also feel that his caregivers/teachers don’t push him hard enough. I have placed him in 3 different daycares within the past 2 years because I feel that my child is being looked over due to his communication issues. This is starting to depress me because I just want my kid to grow up like those around him. I’m sick and tired of teachers/caregivers looking past him. It’s frustrating. Yes I have thought about keeping him home with me and helping him myself but I am a full time nurse and my husband is a postal worker. We have to work to survive. My son also needs to learn to communicate with others so staying home isn’t the best option. Has anyone ever dealt with this before? What can I do to help my son and to alleviate my anxiety ???