H.
My son, who is now a couple of months away from 3, used to wake up the same as yours. I too am a full-time working mother of 2 beautiful children and love to sleep. You know, long before children were involved. LOL!!!!!!!!
I would be sound asleep and hear this blood curdling scream. It would freighten me so. I too asked the pediatrician, and also got nowhere with that. So I had to make a couple decisions on how to resolve the issue.
I was pretty sure that there was no issue like his teeth coming in, I changed his diaper just before he went to sleep, and fed him as well. When none of these things seemed to work I thought that he may possibly be having "night terrors." I looked into this, but there really isn't that much info on this topic.
So, long story short, I purchased a glider and placed it in his room. When he woke at nighttime with this screaming, I would go to his room, sit in the glider and rock away. It seemed that everytime I went in, it got a little better and a little faster for him to go back to sleep. Now it is to the point that we have not had to go into his room the last 4-5 months now and he is sleeping through the night.
Just be patient. It seems like there is no end in sight but have faith in yourself and your child that things will work out and that this is something he will grow out of.
S. D.