Your not out of your mind..... You said you have a disability, so this makes it easier to do.
What you are looking for is not a license for a service animal but to have a certified service dog. There are company's who offer this service. Also, you will need a letter from your vet stating that your dog is not aggressive.
It is against the law for anyone to say their dog is a service animal if the person is not disabled too. Be aware of that. People are not allowed to ask the nature of your disability either.
Patches, or vests are very nice to have on a service animal because it idenifies the dog.
Anther thing that you may want to consider is to have a letterfrom your doctor stating that you are disabled. there are many disabilites out there, but, technically if you are fully disabled for what ever reason a service animal is justified.
For example, a person may say, they are disabled, but are not fully. Some places require proof about that.
I have a puppy that I got for this reason too. I have a letter from the doctor, on full SSDI, and could have my Yorkie certified too.
Pm me if you want sites who certify service animals.