I have 3 working cockers, I work the older two and the youngest one is being trained at the moment. I know some don't agree with me (!) but I genuinely do think that the vast majority of workers need more exercise and stimulation than the vast majority of show types and that they do not make ideal pets for most households, there are many other breeds/types of dog which are better suited as family/household pets for most people/families. My own dogs do need a lot of exercise and stimulation to keep them completely happy, they are very active and energetic dogs BUT they are not what I would call 'hyper'. Alfie my 2 year old blue roan is a 'hot' dog and is difficult to handle when out, he's not been easy to train and walking him is not a relaxing experience but he's very good in the house and I don't think of him as hyperactive, just high drive and energetic as he was bred to be.
All of mine have their mental moments where they play fight and charge around, if they're out on a walk they can do this as much as they want but I don't let them do it in the house as the more they do it the more wound up they usually get. If one or all of them is in this mood I give them something more constructive to do instead like a game of hide and seek or just a chew or a kong stuffed with something tasty. If they won't settle even then and they've had their walks and training that day but are just in a giddy mood then I am firm with them, I don't tolerate this and they get put in a time out on their own for a while to calm down. This is unusual for them though, 99% of the time if they've had their walks etc. then they're very, very good around the house and just amuse themselves with their toys or sleep.
One other thing to consider is the age your dog was when you rehomed him. Many dogs (not all) go through an adolescent phase when their behaviour can deteriorate and they can become more difficult to live with for a time, a bit like a teenage human. This can strike any time between around 7 and 18 months and can last for some time.
Food and diet can also have an effect on dog's behaviour with some brands of dog food being very high in additives etc. which is basically the equivalent of feeding a child skittles and those bright blue drinks. The usual culprits for this are Pedigree, Bakers and some of the supermarket own brand stuff.
Lastly, some environments can make dogs more hyped up, I have a friend who has two young kids and her house is a lot more active and 'buzzy' than mine; if I take any of my dogs there I definitely notice that they become more 'wired' and I suppose a bit more hyped up because there are invariably kids running around and a lot of noise etc. going on with people getting up and down all the time. Conversely my own house is pretty calm and laid back as it's just me there and the dogs' general behaviour at home pretty much reflects that. Please don't think I'm suggesting you live in a mad house or anything but the general vibe and environment of a house, particularly one with young children around with the noise and activity that entails most definitely can have a bearing on a dog's behaviour, particularly a young dog and one which has been bred to have a high drive anyway.
