Hugs, and welcome. You are not alone - take a look through these boards
How old exactly is your LO in months? What is his usual daytime routine (WU time, nap/naps and bedtime)?
I'm assuming from the fact that you see the paediatrician that there are no health issues known that could be affecting sleep eg reflux, ear infections etc?
I'm inclined to agree with your paediatrician in the sense that this is probably not that you have a child who is 'allergic' to sleep, it just sounds like he doesn't know how to go to sleep by himself so every time he stirs in the night (as all of us do every 90 mins or so) he calls out for help to get back to sleep. How do you respond to those wakings? How do you resettle him? Where does he sleep at night and for naptime?
I suspect some sleep training would greatly improve things for you if all other things are well. It will be hard work, and there will be crying but you will be there with him to comfort and reassure until he learns how to settle by himself. We'd love to help you with a plan. I would imagine it would take a good 1-2 weeks initially and possibly a bit longer, but you should be seeing improvements during that time. Does that sound like something you could commit to?