Should I be concerned about my 3 year old?

[Porgies]

Poor sleep, he very rarely sleeps through the night.
Speech delay, has only just started forming sentences, pronounces a lot of things incorrectly. (Nursery have referred him for speech therapy)
Not yet potty trained, no interest in using the potty/toilet despite reading books, using sticker charts etc.
Very clingy to me, rejects his dad, hangs off my leg in social situations.
At the same time goes wild in public, runs away from me, not always conscious of danger, very clumsy and is always banging his head!
Other than that he’s very funny, always dancing, singing and making his brother laugh, loving, enjoys role playing, being outdoors and art.
I believed all the above was average 3 year old behaviour (especially for a covid baby!) but in the last week he’s started blinking a lot and of course dr google has come up with lots of behavioural/neurological disorders as the cause.

Well he has a slight speech delay, but that's fairly common and the fact he's still progressing rather than at a standstill is good.

The blinking thing is strange, so take him to the GP. It could be a nervous tic, discomfort in the eye or sight problems.

My youngest was 3 when he was potty trained, and honestly he was a pain about it. There were two failed attempts that lasted a week or two as he was absolutely against it and didn't give a fuck about sticker charts or potty books. He is an incredibly stubborn child generally (mum says he gets it from me, the witch!)

Get a wrist strap or backpack reins when you're out with him and as time goes on try him out just holding your hand in places he won't get lost in the crowd or hit by cars. Banging his head off everything...well, he is a small child. I've witnessed my kids hit their heads/elbows etc in ways I didn't know were possible, surprised they have any braincells left!

This is probably going to be the least helpful response you receive but is there anything he watches in TV where the characters have big blinky eyes? Because when my daughter was three, she started doing the same thing - I was very concerned, took her to the GP and all sorts. Long story short, she was watching (too much of) a programme called Simon which is about a rabbit and his family and friends who all have massive, blinky eyes…. She was basically channelling a cartoon rabbit. I’m only popping on her to say that it’s very likely to be something minor but if you’re worried, there is nothing wrong with a trip to the GP. Hope he’s okay - the other stuff wouldn’t give me cause for concern.

It could be or could not be. Keep doing the right thing, use reins in public, be consistent. I’ve seen kids like this who were perfectly normal, kids like this who later had problems and “normal” kids who later had problems. Keep talking to him, reading with him, playing with him and he will absorb it whether you see results or not. Nobody on the internet can tell you anything without seeing your child, being a professional etc.