I really need some help.
All of a sudden my boyfriends dog has started acting strang... his tail is stiff and in the air and he just won't settle and just doesn't seem interested... we have tried playing with him which he loves, taken him for a walk, let him out in the garden, turned the fire on because he loves to lay in front of it but he just doesn't seem to want to do anything... when he comes to settle next to one of us he lasts for 5 minutes and jumps up which isn't normal with him and starts running around like a mad man... were worried if anyone could help that would be great... he's a 6months old staffordshire bull terrior and is a really loving dog and has a great temperament and is very loving but tonight he just doesn't seem himself.

Every dog has its own set of species, breed, age, or even gender. Your dog may be not himself of being "depressed" or sick. Outburts of running may be just apart of how his breed acts, I'm not sure. If you can get in contact with a vet, make sure you let them know he hasn't really been himself lately. The vet will try to help you and your pet I'm sure :) I hope this helps

There are a few possibilities.
With any sudden changes in behavior my first advice would always be to consult your vet but we will see if we can't come up with a solution here.

Do you live in an area where there could be squirrels or other animals in your yard? It is possible he is hearing noises and standing to attention because of that.
Does he scratch at the door or try to get outside a lot?

Another possibility is that at 5 months he is starting to get a bit more testosterone and there may be a b*tch in season on your street which he can smell that is making him act strange.

Does he seem sick at all? The way I read your question was that he just seems to be more 'hyped up' than normal?