I have a 11 year old collie x GSD who is normally really active, but recently has become really lethargic. He used to dart around the woods playing with other dogs and chasing squirrels, but now he has become really slow, its like he has no energy. He recently had a bit of a wheezing cough and puffy eyes like he had a cold. I am really worried as he is not normally like this and I know that somethings is wrong. Its like he is depressed.
Do you have any clues or solutions that will help pick him up.

Take him to the vet. There's 101 things that could be causing those symptoms, and most of them are easily treatable. Make an appointment for this afternoon or evening. Time could be critical.