All dogs and breeds go through different stages throughout adolescence,
From happy, go lucky puppy - who loves everyone and everything that moves to one that is terrified of everyone and everything, becoming very self aware both in hormone changes and the way other dogs will now no longer look upon her as a cute harmless pup.
Her time for being tolerated by other dogs is now over and a natural instinct of survival has kicked in to protect herself, this fear and danger period is there for a reason it is a normal behaviour some breeds start earlier, some later, what your pup is going through may be a worrying time for you, but is all part of growing up for a pup, they go from not caring about anything to becoming aware of all dangers around them and this is exactly how a pup will react, it is called growing up.
All you need to do is make sure that her fears are never realised, keep her safe lead her immediately when meeting another dog or human she does not know, give her no ammunition for her fears, above all else do not be apprehensive yourself, her fears are heightened and so is her readings from you. She will come out of this stage soon enough as long as she is not attacked or looses faith in you her owner.
Once through this stage she will be relaxed and comfortable once again, and once she has reached full maturity she will be a happy relaxed dog, do everything you can from now onwards to protect her from other dogs, who do seem to have a penchant to attack adolescents so many are mentally scared through owners being too relaxed at this vital growing up stage, she is at her most vulverable time right now and needs extra careful handling from you.
Just stay vigilant, keep calm use a soothing voice and act as normal as possible.