Proin Medicine for Leakage & Aggression? Experiences?

Hi All. Our puppy just turned 2 years old and we have had her since she was 6 weeks old. She has always been a very active and happy dog, who needs to burn a lot of energy. We have adapted our lifestyle to more walks and more fetch with her. She recently started taking proin, which helps dogs with urinary incontinence. She is border collie/lab mix and developed this condition a year after getting spayed. She can control her bladder, she just "leaks" little puddles when laying/resting. So, when she gets up there will be a puddle there. The Vet originally prescribed her Proin last winter. We noticed nothing that affected her negatively from the medicine and it also took care of the leakage, so we were ok with having her on it. After a few months the meds ran out and it took a month med free until her leakage came back. After researching Proin more we realized it is a maintenance med and the dogs are usually on it for their whole life. We tried to look into some natural remedies and actually had a little bit of success with Apple Cider Vinegar, but she developed an ear infection shortly after that. We went to the vet to clear up the ear infection and talked about the leakage and they said it is fine to be on Proin long term. So last week, we put her back on the Proin and she has been on for 1 1/2 weeks now. Last night, she reacted towards my niece. My niece was over here 3 weeks ago and was "hitting" my puppy towards her face a few times. I don't think she made contact, but my puppy did not react towards her at all that time. Now this time, on the meds she growled at my niece a few time and snapped at her once. In 2 years the only other time we saw Goldie Growl/Snap was towards a dog she was playing with, she didn't want to share the ball she had. My dog has NOT been around other dogs much or children at all. The dog and cat's she is around she is TOP DOG and I think that played into this a little bit. We are having a baby this month. I am thinking it is the medicine, should I just stop giving the medicine to see if that helps? Should i lower her dosage? I'm so scared about her being aggressive towards our baby or any child, because we DO love her so much and do NOT want to see anything bad happen to lead us to be forced to put her down. Sorry this is sooo long, but this is just killing me and I really need advise on tips for this and how to try to handle the situation!? Or any tips for aggression in dogs? Thank you so much!!!