Clingy 3 year old

[Germoo]

Hello everyone
Just wanted some advice. I have a very clingy 3 year old DS. He can't do anything without me and is even horrible to his dad. He says things like I don't like daddy. Stop talking I'm talking to Mammy only. He screams the place out of it if I have to even go to the toilet and hates being with other Children his age. Has no imagination and is very logical. We have tired all recommended tips by health visitors but nothing works for us. He even knows how to use the toilet but will prefer to wear nappies because he knows I'll change him. I'm trying to be calm and patient but this clingyness has being going on since he was 18 months and there is no improvement. I find I'm losing it a bit now.
He goes to nursery 3 days a week while I work but short hours so I'm with him most of the time. He loves it there the usual screaming when I'm leaving him in the morning. Going on since January. They told me last week he will not mix with other children and will just hang out with his key working. They have discussed it with me and said this is a bit difficult as they have other children. It will be more difficult when he starts in the pre school in September
He had a Assessment with the HV a few weeks ago and they will reassess in 6 months
Sorry for the long post but it's getting more and more difficult to be around him especially when we are out and he's practically trying to climb back up into my womb 😂