@WhatAMum01 
Cup of Epsom salts in a hot bath every other bath & a dose of magnesium liquid every day also zinc drops & fish oils.
I buy all this off amazon. Spent years experimenting trying to find the right combo, if you want specific items let me know, happy to share!
Lush sleepy wash in the bath & lush sleepy cream on when out the bath.
Then he has melatonin every night. (Prescribed by his consultant)
Don't expect overnight miracles, takes time.
My ds is 5 and a half. (Asd, adhd & learning difficulties)
Do you get dla? Carers allowance? Disability elements of tax credits? All this helps to pay towards this stuff as it can get expensive.
He will get easier, even if just a little bit. When you have it hard all the time even just a small improvement makes the world of difference.
Ds is still difficult, he is very obviously autistic and has so many symptoms that it completely rules our life, some days I cry and wonder how I'm ever going to get through another day, but looking back to when he was 4 compared to now almost 2 years on he is definitely easier in some ways (but much harder in others) things change they honestly do.
Ds is verbal, although nothing like age appropriate. He has disordered speech, very speech delayed, lots of echolalia, no conversations, can just about answer yes / no questions, but can now communicate enough to get his basic needs met - want drink, want food, something is hurting him etc he couldn't at age 4.
Ds will be back to school in 3 weeks so will give me a recharge of my batteries again.
Look at these two books these are useful, particularly the raising a sensory smart child. (will add pics.)