3 year old boy so active?

So my little boy is so wild. He will not sit for more that 5 mins but in the last couple of months it's gotten worse. Since January the nursery are even saying he isn't processing or understanding what they are saying to him. He will literally just run up and down the livingroom for hours. Everything down to meal eating, he needs to eat it on the move. Hes hiting his sister who's 9 and being horrible constantly. He has tantrums off the scale which can last over an hour. Nursery are saying he's hitting with toys but not understanding what he's done. We had someone out for his behaviour who said try "naughty step" and "sticker chart" but he doesn't understand the sticker chart and now he puts his toys on the step for 3 minutes like a game. He's speech delayed and has glue ear so awaiting grommets and referral for speech and language. My husband works away and to be honest I'm at a complete loss. I can't even do simple tasks. A women was out doing my hair yesterday (she's been my hairdresser for nearly 10 years) but she was shocked and had to rush my hair cut then I had to dry it myself. He thinks he's hilarious and doesn't get how awful the stuff is. I just don't know what I'm doing anymore. I'm waiting for the health visitor to come out and assess him but not sure what she's assessing him for. Could just use someone to talk to who is going through the same with their child.