This service dog being trained while at a local football game got tired

You're a dog trainer!? Can you please help me!? I am so distraught in trying to find one here for my puppy's problem and his current classes aren't helping with this issue... my 8 month puppy has only had mostly negative encounters with other dogs and now fears them. They've been out of my control (for example, walking him at our favorite park when an unleashed aggressive dog came out of nowhere and attacked him and drew blood). Now my dog is afraid of other dogs and responds negatively. He will start to greet extremely slow and the moment they get in his bubble he tries to attack. Please help I don't know what to do! He's in petco training and my trainer told me I'm on my own about this issue and they never even let the puppy play time happen since day 1 so he has no clue how to interact with dogs since they've all been negative! (Even at many dog parks when we go out of town, my town isn't dog friendly and therefore doesn't really have one until recently but it's extremely small and he still was aggressive there to puppy that was very playful). Please tell me if there is something I can do to make him realize there is no reason to be afraid and mean? :(

/r/Eyebleach Thread Parent Link -