Hi Saxon -
Sorry to hear you're having issues with derealization. It can be quite disconcerting some days. I get both derealization and depersonalization. Sometimes it's just one or the other, and other times it's both at the same time. This has been happening to me since I was a child, but I didn't have a word for it until I was 30 years old. (I'm 41 now.) I used to call the episodes "grey outs", because when I'm DR'd, most colors tend to fade to grey. That's actually one of the main things I use to help bring the world back into focus - color. The one color that I can still somewhat see is red, so I'll focus on the red in my surroundings. If I'm going to a meeting, I'll bring a red folder. It sounds a bit odd, but it works.
There is no cure for it, per se, but they have done some studies and found some medications helpful for it. I have heard of people using SSRI antidepressants and benzodiazepines with some success, but then others feel no benefit from them. It is something a psychiatrist would probably need to treat, though, as it really is out of the realm of the family physician.
There is a good book available about depersonalization and derealization called
Feeling Unreal: Depersonalization Disorder and the Loss of the Self by Daphne Simeon. You don't have to have Depersonalization Disorder to have DP or DR. It can often come on with depression, trauma, anxiety, marijuana use, or even when you're just tired in a milder, transient form. It's our brain's way of protecting itself from psychic pain at times and is a normal, helpful mechanism in certain situations. Sometimes it gets out of whack, though, and that's when it becomes a troubling condition.
You mentioned remembering when you first noticed it, while playing with your dog. Did anything traumatic happen in the days or weeks shortly before then? Have you ever smoked pot? How long had you had your dog? Sometimes it's helpful to narrow down what the original source of the dissociation might have been and then work through that with therapy.
The next time you feel DR'd, take a good look at your surroundings, as unnerving as it may feel...is there anything that stands out to you as seeming "less unreal" than the rest of it? Focus on that and see what happens.
Oh, and welcome to PC.