I had a little chuckle at your post! Very cute. I've made these mistakes, and lots of other people have too!
To start with, you're going to want to stop letting him on your couch and bed. This is where humans sit, not dogs. If he is following you around when you go to the bathroom, bedroom, kitchens etc... ask him to sit and wait in a designated area with a pet bed or his blanket, (this will take some work, a long stay while you are out of site is one of the hardest commands to teach and master). Start by turning the corner and counting to 3 and come back and praise like mad if he hasn't moved. Each time increasing the time you are away until you are comfortable doing short tasks while he is in stay. A bone or a chew toy left on the pillow are also great distractions.
Protocol's for relaxation are great ways to put you in the alpha role and your dog not so anxious when you aren't around. Make him sit before giving him his dinner, make him sit at the door before going outside, make him sit in front of you to be petted, make him sit before giving him his toy. If you normally leave food out for him all the time, stop. Go to a twice daily feeding and you decide what time of day he'll be fed. Make him sit for his dinner. If he won't obey the command – no dinner. Walk away and ignore him. Bring the food out later and tell him again to SIT. If he understands the command, don't tell him more than once. He heard you the first time. Give commands from a standing position and use a deep, firm tone of voice. This is just setting your dog's mind at ease as you are giving him a task to concentrate on. It's tedious but does have very high success rates.
Practice being alpha. Stand up straight with your shoulders back. Walk tall. Practice using a new tone of voice, one that's deep and firm. Don't ask your dog to do something – tell him. There's a difference. He knows the difference, too! Remember that, as alpha, you're entitled to make the rules and give the orders. Your dog understands that instinctively.
Natural leaders and social climbers aren't going to want to give up their alpha position. Your sudden change in behavior is going to shock and threaten them. Your dog might act even more aggressively than before. An alpha dog will instinctively respond to challenges to his authority.
An alpha dog already knows that he can beat you in a physical fight so returning his aggression with violence of your own won't work. Until you've successfully established your position as alpha, corrections like hitting, shaking, or using the “rollover” techniques described in some books will not work and can be downright dangerous to you. An alpha dog will respond to these methods with violence and you could be seriously hurt.
You're smarter than he is and you can out think him. You'll also need to be stubborner than he is. Alpha dogs are used to being fussed over. In a real dog pack, subordinate dogs are forever touching, licking and grooming the alpha dog. It's a show of respect and submission. For now, until his attitude has shown improvement, cut down on the amount of cuddling your dog gets. When he wants attention, make him SIT first, give him a few kind words and pats, then stop. Go back to whatever it was you were doing and ignore him. If he pesters you, tell him NO! In a firm voice and ignore him some more. Pet him when you want to, not just because he wants you to. Also, for the time being, don't get down on the floor or on your knees to pet your dog. That, too, is a show of submission. Give praise, petting and rewards from a position that's higher than the dog.