Out of control 3 year old

[mum_28]

My boy has just turned 3, he was ok up until about 2 1/2, he has always been energetic and never been one to listen to what hes told.
He has become out of control to the point i dont know what to do anymore.
He is on the go from the minute he wakes up untill 11-12 at night without a break in the day.
I try to take him out of the house but im forced to pack up and come home, he runs around like a maniac destroying everything in sight, i try the pram but its a screaming match and he gets out and does the same thing.
He yells at people, he swears, spits, hits, throws things across the room and throws massive tantrums when he doesnt get his own way or something wont work the way he wants.
I have a 6 month old girl and i cant leave them in a room together.
I dont know what to do, could he have a medical problem?
Even if we try to do activities with him it lasts 5 minutes untill he snaps and throws things everywhere and starts the swearing and screaming.
i cant even take him to playgroup as other mothers look at me as if they dont want us around.
I thought it was terrible 2's but its getting worse everyday to the point i am now falling into a depression.
what can i do?

[allmymarbles]

Is he getting enough sleep? If not, why? Sleep apnea perhaps. This is more common in children than one would realize.

And what about diet? A diet heavy in sugar can make a child hyper.

[mum_28]

Hi thanks for your advice!
i havnt had him tested, but i did a bit of research on what you mentioned about the Oppositional Defiance, and everything sounds very exact to what he shows and how he acts.
Although i did forget to mention that sometimes he is capable of actually sitting down and watching a favourite tv show for hours, and then after a while he snaps again.
I will look into getting him tested, how would i go about that? And what do they actually do?