I got a doggo and it sucks

File: IMG_20170420_102438.jpg (805KB, 1332x1751px) Image search: [Google]

805KB, 1332x1751px

Don't mind me, I'm just ranting.
So two days ago a dog appeared outside my back yard asking to get in. She sat there for a while before I realized, so I let her in. She got really happy. She's just a kid, probably around 1 year old.
After a little while, I realized it's just not going to work. She's a big dog, and she's really hyperactive. My cat got really scared of her and barely comes down anymore. The dog already proved to be coercive in many ways, now I have all the doors to the yard closed, and I can't go out without the dog getting all excited.
I'd read something (a clickbait title actually) about "people who own dogs are more outgoing", which seemed to imply they're happier. But now I am depressed. My cat can't roam about freely, and neither can I. All I can think of is getting rid of this dog, I already got flyers all over the place hoping it belongs to someone, but I don't think she has an owner so I'm stuck with her, I'm going to put up adoption flyers when it feels reasonable. Perhaps a week.
So in the meantime, I am stuck with this dog that wants nothing but to play, and who gets all whiny whenever I come inside.
Maybe I'm not cut out to have a dog, but this absolutely sucks. The worst part is that I don't know how long I'll be stuck with her, and all I can do is wait until someone comes to either claim or adopt the dog.
What's even worse, she's really happy, and I feel like shit for feeling annoyed with her presence.
Pic is her.