Am I over-thinking it or could it be?

Hi all, I really hope someone can help me as I don't know where else to turn.
My little boy is two and a half years old and just recently I have been exploring the notion that he could potentially have some type of ASD.
I have only just begun this past week to look into it as he seems to be becoming more frustrated by the day. He makes a lot of sounds/noises but still hasn't said his first word.
This makes it increasingly difficult to understand what he wants sometimes, as he does point to some things but he will becomes very upset if say, he points at the sink for a drink but I give him water instead of milk. Or if he points to the fridge for food and I give him some blueberries instead of a banana. 
This entire time I have just assumed it's as simply as he can't speak so it is making him upset that he can't communicate properly but have started piecing some things together and this is how I have come to this conclusion. Here is a list of red flags that are personal to my little boy, from what I understand from my research:

- Odd behaviors and play. The first handful of times we ever  took him to the park (near his first birthday), he wasn't interested in playing on anything but he would walk around picking up all the litter and handing it to us. Eventually he stopped doing this as we had to persistently tell him no because it was dirty. So then he started exploring the park more, but he would always run around the entire park without looking back/checking in to see where we were and refused to hold my hand or even let me hold onto the back of his shirt/coat so I would have to run alongside him to keep him safe. The only time he would stop would be to repeatedly run up and down a small hill which he would do for about half an hour or more or until we picked him to up to leave.
- To this day he refuses to hold my hand/or let me hold onto him when he is out of his buggy and will lay down on the ground every couple of meters or so until we reach wherever we are going.
- He has never really played with his toys properly. There are only a few ways he plays and that is:
a) if he can find a way to take it apart, he will do it without fail and usually it doesn't take him very long 
b) he will use a container or box and find a set of toys such as dinosaur figures or cars and put them in the box, and then tip them out, and then put them back in, tip them out, back in etc.
or c) he will line up, or stack things and then mess it up/knock it down and repeat .
- He often does not respond to his name, usually I will have to say it anywhere between 3 - 6 times before he will look at me.
- I often find him 'zoning out'.
-He will only very occasionally smile back when you smile at him.
- He does not seem very interested at all in anyone other than me and his Dad. When we are the park he will actively only use apparatus where there are no other children playing on it and if another child comes over while he is on something he will nearly always leave and go somewhere else. Also when someone who isn't me or Dad speaks to him, he covers his eyes and won't look and if they try more than once or twice or put their hands near him he will usually start to cry.
- He gets very easily distressed, like if he cant fit all his blocks in one box or if you offer him something he doesn't want and at many routine parts of the day for example teeth brushing, nappy changing, having his face wiped, nails cut etc.
- When told no, he will pick up the nearest thing and throw it, every time without fail (which worries me because we have also a 6 month old daughter who by the way he absolutely refuses to be touched by or even sat next to by her)
- He has no sense of fear or danger at all and he also seems to have a pretty high pain threshold which is sort of handy as he is incredibly clumsy.
- He seems to repeat the same set of sounds and noises, all day every day. It often sounds like he is having a conversation with himself but there are no words just a lot of babble in different tones. I have also caught him sometimes erupt into fits of hysterical laughter for literally no reason at all.
- He seems to hate sitting in or being put on anything new for example, sitting in the dentists chair or a new highchair or buggy. He usually starts to cry/scream.
- He has a hard time transitioning from one activity to another and will become almost inconsolable such as, when I turn the bubble machine off or when we have to leave the park.
- When he gets upset or frustrated and starts to cry, he will throw himself on the floor and sort of thrash around and often hurts himself accidentally in the process
- He refuses to eat any/all types of meat and absolutely flat out will not even try anything new food-wise. He also has a few odd preferences such as he will eat chips and potato waffles but won't eat mash potato or roast potatoes. He wont eat pasta but will eat spaghetti etc.

There are a few other things but you get the general idea. He is an intelligent boy and I just want to help him as I know in my heart that something is not quite right. Am I paranoid? Is it most likely he does have something like this? Any advice or insight would be truly appreciated before I go ahead and start booking for the assessment process which I'm sure is going to be lengthy and stressful on all of us.
Thank you