Try to do some desensitization training. Practice commands like watch me and sit at a distance and SLOWLY work up to closer and closer distances. Avoid tensing up when you see that dog because that will increase her excitement and agitation. DO NOT yell at your dog (idk if you do, just putting this out there.) as that will also increase the tension. Also... is your dog fixed? Is the other dog fixed? That could be part of the issue.