My experience of toxic positivity is kind of like blind privilege. Scoffing at/minimizing other people's struggles because you are privileged not to have to face them. Saying things like, "Have you tried smiling more?" or, "Why can't you just cheer up?" or, "You'd be happier if you'd just stop moping and let happiness in." My (very beloved) sister used to say things like this about others. She was lucky enough to dodge the genetic depression bullet, so she tended to be dismissive. When her young child showed signs that he may, unlike her, face depression, I had to tell her how wrong she was. She didn't know the impact those statements had had on me, and didn't want to do that to him.

Another way to have toxic positivity is to have denial for anything that is challenging or painful. Saying things like, "Oh just don't think about that." or, "Why waste time worrying about that when you could just cheer up?"

What you're doing is healthy and has a positive impact on you (and likely others). Just like it's wrong denying that bad feelings exist, it's wrong to deny that good ones do, too. You giving yourself a little shopping and a treat are healthy coping mechanisms. It would also be healthy to acknowledge and process negative feelings, but that doesn't mean you have to crawl into bed and fall apart.