Canine Freakus Outus

I have an ongoing issue with my canine.
Since moving from home to apartment, my dog, Veto, is absolutely FREAKING OUT!!!

I am aware that the dog's sense of smell is a gazillion times stronger then us, but since when did that translate to frothing at the mouth and whining? He looks rabid every time I walk him. Not to mention he is pulling on the leash so hard he is dragging me about and making this coughing choking noise. We get a few looks from the other residents.... probably wondering if the front office verified this psycho pooch got his immunizations.

Once upon a time, I took Veto to the local dog park. He hid behind me when a feroceous 10lb Boston Terrier arrived at the scene. To back up, Veto is a 50lb shepard/doberman mix. This terrier was smaller then his head, but must've been scary to Veto somehow.
There's an on site dog park in the complex, the main reason we signed up here as opposed to the other thousand apartment complexes within 5 miles. I thought we would be ok, he'd just be a big chicken as usual and go about his 'business' quickly in order to get the hell away from the other dogs. But oh no. He goes from chicken to psycho rabid dog, barking and running at every dog he sees. Now I have to wait until there isn't a single soul near the dog park to take him.
And he still froths at the mouth and whines.

He's also started doing a cat impression by lying on the back of my now deformed couch so he can look out the window. He can see a teeny tiny part of the dog park from this position. He lets you know if he sees any movement by whining and barking and jumping about, although I must admit there's been improvement as he used to go through these motions when the wind blew or a bird flew by. You could tell his depth perception was a little muddled being on the third floor where the birds fly by; as opposed to his usual 'chase them when they land on the ground' vision.

I'm hoping we get past this because I truly feel bad for him. I want him to make a friend, get along well with others, be polite. All the things everyone wants for their children, only mine's four legged and drools white foam.