How can we help our puppy build her confidence?

While we were walking our 5 month old yellow lab, she was attacked by a neighborhood dog. It was pretty bad - she wasn't hurt but she was shaken up to say the very least. The poor little thing wouldn't stop crying afterward. She's 8 months old now and is afraid of almost all dogs. I think the other dogs can sense her fear because she's getting bullied - I can't even count how many times a dog has gone after her...unprovoked by her. We've been bringing her to a doggy park to try to introduce her to other dogs but she hides under the picnic table if a dog even gives her a look. Any suggestions?