[DJDB]

My only advice is to stop feeling like a failure. Your dog reads your emotions - probably better than you do. You are afraid and anxious, likely before you even leave the house. You're probably putting tension on the leash. When another dog approaches she can feel your anxiety. Calm and assertive is how you have to be. And, if you've watched the Dog Whisperer, you know that timing is everything. Really watch your dog to see the signals she gives off BEFORE she escalates her behaviour. That is the point that you need to de-escalate her, not after the fact.

I understand that money can be tight. Have you thought about a doggy daycare where she can be around other dogs without you there? It's likely cheaper than a trainer, and that might be just what she needs to learn how to behave around other dogs. The doggy daycare in our neighborhood costs $10 for half a day. Even once a week for 2 hours might help. But again, you would have to be cautious of the attitude you're giving off if you're dropping her off. You MUST be calm and confident, not afraid.