So frustrated that I just want to cry

All day I've been waiting for my SO to get off of work so that he could go with me to get a 5 month old puppy that I was going to have registered as a service dog for myself since I have anxiety attacks when I'm out in public alone. He waited until just now to tell me that he doesn't think it's a good idea and I've already gotten my heart set on it. Not only would I have a little furry friend to love along with my precious kitty but I would also have some support when I'm out shopping alone or whatever. I'm going to go get her regardless because I think it would be better to have the dog to get acquainted with him and myself and then once the baby comes along the puppy would be a year old and perfectly ready to be around my child. He said that in a couple months, his friend has some puppies that will be freshly weaned from the mama and ready to find homes. Why should we get an actual puppy puppy VS a dog that would have a little bit more control over excitement and such? Am I being stupid and overreacting? I just really wanted a little helper especially with me being pregnant and an even bigger worrier now. 😭😔