Looking for advise

Backstory

I have a 7 month old aussie. We got him when my son was 1 year old and due to me being a stay at home mom and a new dog owner I haven’t taken him to any dog parks. Whenever we go on walks it’s always with my son in the stroller. I take the dog almost everywhere we go and try to take him to my moms house whenever I have to leave for more than 4 hours. Basically he’s around people most of the time he loves my siblings and my family. He’s super good with my baby but as soon as we got him I noticed he was super nervous around other dogs.

I started to take him on walks more often for him to get used to seeing other dogs walking in the park but one time as I was walking him through our neighbor hood with my son, a pit bull ran out of the corner and jumped him. The pit bull didn’t seem friendly to me at all, I got scared and started yelling at the owners to take their dog because my puppy was running in circles from him and the other dog would just chase him and jump him he was a lot bigger obviously. The owners ran out and called their dog I was so shaken up. We got home I made sure my puppy wasn’t harmed in any way and he wasn’t but he was so scared and nervous. Ever since then he’s scared of other dogs. We were at the pets clinic and there was a 6 month old Labrador there, he wasn’t even looking at my puppy but as soon as my dog seen him, he peed himself. I’m not sure what to do. It doesn’t make sense to me to take him to a dog park because he’s clearly scared of dogs( big or small ) any advise would be greatly appreciated