I'd talk to your landlord about getting an Emotional Support Animal. The Fair Housing Act does allow you to have one regardless of his policy, but it wouldn't hurt to say something first. I say ESA instead of service animal because the latter has a specific set of requirements according to the Americans with Disabilities Act, which an ESA doesn't. You would still need something stating why you need one, though. I know this because I also have PTSD and was trying to train a dog to become a service animal instead of an ESA so I could take her to crowded places where I normally have anxiety attacks.