Is there a real reason to worry?

Hi all

I have just started the journey, we have autism in both sides of the family (my cousin and my wife's cousin).

Our 3 years old son has many worrying symptoms (I will describe later), I heard that the diagnosis journey is very long (3-5 years), we have just got our first appointment, I need some early advice if we need to really worry about this and continue with the diagnosis process and consider the worst, or we should have some hope and that it might not be autism.

Please check this description and comment from your experience.

• Many times refuse cuddling (but he sometimes ask for that)
• Focus on the same thing a lot (for example, a toy or a thing e.g. playing with travel bags the same way for a week or more and refusing us taking them away.
•  Has more mechanical skills than mental (loves to climb from a very young age)
• Very aggressive, hit and bite other childrenan parents and throw things which break, and doesn't listen to most instructions (do this and don't do that).
• Shouts in public places with no easy way to calm him down.
• Late speach (2.5 years to start saying very few words, and when 3 started saying about 100 words most in Arabic and some in English with 2-3 words sentences).
• Regressed skills and speach (by 3 years old he started degrading speach, stopped using most of the sentences he used to say, and reduced usage of words, he stopped asking for things but he rather points and says this this this, and if we don't recognise what he needs he enters into a very aggressive and uncontrolled state of shouting, crying, hitting and almost unconsciousness, later after two weeks he started using sounds rather than words to ask for help for example, usage of speach had reduced massively, he also learnt toilet by 2.5 years and after we've left him for a few days with a childminder he stopped, and he requires a nappy now).
• Eye contact is minimal (mainly happens when we initiate it, and even when we initiate it, he sometimes ignores us looking and looks to other directions without a chance to keep his sight in our eyes even if we are smiling and so on, we noticed that from very young age (less than a year old), sometimes he responds to our try to look in the eye and looks, but in a couple of seconds he slaps us on the face while laughing.
• Obsessed with details, he notices and mentions small defects / dirteness in items and keep referring to them again and again and again.
• Keeps mixing between opposite things like cold and hot or pain and heal,...
• He has a lot of small and large car toys, and he loves to order them in a long line from a young age (around a year old).