My God...

Is THIS what it feels like to be a parent?
My family has gone to Sydney for the weekend, and I'm at home looking after the cat and the dog (who is sitting on my lap right now and making typing very difficult.)
On Friday, I had to go to university to hand in an assignment. Because of delayed trains and a second-rate bus service, I was home quite a lot later than I had planned to be. I spent the time away from home worrying about my dog. About how lonely she would be on her own, about whether I'd shut the gates properly so that she wouldn't get on the road, about whether I'd remembered to put her food and water outside for her, about whether maybe her water wasn't clean enough and maybe I should have changed it. Not to mention "what if a dog-hating maniac gets into my yard and cuts her in half?"
When I got home, everything was fine, I got a warm welcome, and the state of ok-ness was the greatest thing in the world.
That night, she insisting on sleeping under the covers on my bed. I was worried that she wouldn't be getting enough air, and put her back on her bed a number of times. Each time, she came back under my covers. I spent the night panicking about her air supply and waking up to check that she was still breathing.
Last night, I was more relaxed, but still vigilant.
My main concern for this weekend has been keeping her happy and healthy, making sure that she is fed and hydrated and not bored. And every second has been spent worrying that I'm getting it wrong.
Is this what parents go through? This worry, every day, for years, for DECADES? How do they COPE?

*Note- I know that this post doesn't talk much about my cat. My cat is fine on his own and is a lot better at looking after himself than my dog is. That doesn't mean that I haven't been periodically finding him and checking to make sure that he is breathing.