I agree with the idea of going to a shelter and meet the dogs there. And if you are looking for campanionship I’d recommend a dog over a cat.
I used to be a cat person - I liked dogs well enough but I never thought of getting one, I always had and loved cats. Then, last year, my brother adopted a cat from a shelter. He asked me to come with him, calm the cat in the transport box while he was driving, help him carry stuff…easy! You can already see where this is going, right?! 
We walked into the shelter and the first thing I see is this small white ball of agressiveness, barking its head of at me… and I immediately fell in love, 
I told the shelter lady “I’ve never considered a dog, but… what about that one?” and it turned out that Amy (the white Chihuhua) had been turned in together with her two friends Nelly (Chihuahua as well) and Skippy (Minipinscher). They had been together all their life and the shelter wouldn’t seperate them.
My first reaction was that I could never get THREE dogs! But then I walked into their crate and met the other two and there was this absolutely clear feeling, that these dogs belong with me.
I adopted them about six week later and it was the best decision I have ever made.
Yes, it is a lot of work. Yes, they sometimes smell and you have to pick up poop and it’s a lot of responsibility but you just get so much back!
I still like cats, but IMO dogs give you a kind of companionship that cats don’t. 
You said you don’t really like small dogs, but I have to say that I’m happy with my toy breeds - they are real dogs, with dogs’ personalities, despite their size.
Plus - on the practical side - they don’t poop as much as bigger dogs, they don’t need so much space and in a pinch it’s easy to carry them. 
I am lucky that I’m allowed to take my dogs to work, but they can and do stay alone at home sometimes. They are very relaxed, now that they have a home, they hardly ever bark, unlike in the shelter.
When I tell the story how I got them people usually say “the three were lucky to find you” but really I feel lucky to have them. They make my life so much richer.