Interesting that nobody has mentioned how the time of day messes with your perception! Light conditions change everything. Sunset colors and shadows can make ordinary objects look completely different, especially when you're tired after work. Same thing happens to me on the coastal highway sometimes - the sun hits the water just right and I swear I see shapes that aren't there.
Actually read something about how our brains treat calendar events differently than just trying to remember. It's like the act of writing it down, or typing it in, frees up the mental space. So @karenb97, that feeling of "wait, that was when?" is totally normal. The article said our memory for future plans is pretty bad on its own. Maybe it's just me but I have to put everything in my phone now too, or it's gone forever.