Is it ASD or Apraxia- please help.

[Aycddi]

Hi All, I have a 17 month old son. He never really did back and forth cooing when he was infant but the doctor always said he is fine. his motor skills were a bit delayed too (sat independently at 8 months and walked independently at 14 months). He had 2 words with no meaning attached at 12-13 months but then suddenly stopped it. So around 14 months I got very concerned as he had no words, no gesture except clapping, no proper play skills. I started working with a private ST (3 hrs a wk) and OT (2 hrs a wk). and at home had daily 2+hrs floor based play sessions. The play sessions and my ST's suggestions worked wonders for us so far. My little Boy who was not able to follow our pointing constantly points now showing me birds, bunnies, dog, trees, CARS and to show what he wants. I don't know how but within this 7-8 weeks from no words we are at almost 20+ words and shows additional 50words in books and flash cards. We had Early Childhood Intervention Autism assessment last week they said he is doing great as a 17 month old and doesn't have any red flags yet - truth be told my son was so happy on the evaluation day, he even surprised us with his responses. Now this was the good part. But I do have some specific concerns -

Regression: when my son was around 12 months he did have 1-2 words (i.e. mumma, dada) but most of the times without any meaning just babbling and also used to show his belly by lifting his shirt when asked. At 13 months he completely stopped those. That really scared me. I am confused was it regression - if yes then even though he is making such good progress right now should I keep worrying about regression?

The Diagnosis of private Speech Therapist: "mild to moderate constrictions in the DIR® Functional Emotional Developmental Levels'. Underlying contributing factors are sensory processing differences, sensory modulation difficulties, and challenges with motor planning and sequencing. And Mixed Receptive-Expressive Language Disorder (ICD-10: F80.2) and an Oral/verbal Apraxia (ICD-10: R48.2).” ---- I am just struggling to wrap my head around it. If I google all these big words they always get associated with ASD.

He will sleep in my arms at night but doesn't like kisses or hugs at all. He always wants to be around us-never wants to be alone and sometimes he just takes my hand to put on his face or while playing come and sit in my lap - so I just thing his love language is different and he shows affection a bit differently. Should I be concerned?

His play skill: he still tries to put everything in his mouth. Its very hard for us to make him sit and play with puzzle/blocks etc. He will drive the car though, look at pictures in books, sometime hug his teddy bear and tries to make us drink from his toy cups.

Even though ECI said no red flags for now- as mentioned above I do see concerns. Has anyone seen cases where the early evaluation did not flag anything but later ASD was diagnosed? Do I need to keep worrying for couple of years about ASD? I have been in such a bad place for last few months but his progress gave me hope.