Thank you so much for that excellent explanation. I don't think I "confused" them. I just wasn't clear on the definitions.Anxiety and overstimulation aren't very alike, so I don't understand why some people confuse them, except for the fact that both are in the brain. Overstimulation is more like a shutdown, there is too much going on, the brain goes into loops about all the everyday scenes that you've experienced during the day, too much light, noise, smells, unusual things - the memories come back time and time again with great detail. Overstimulation is a core feature of autism. Anxiety is excessive drive / energy in response to an emotional, not sensory stimulus. If to sensory, it's to something clearly unpleasant. Overstimulation is sensory, sometimes also too much information - complicated procedures, many people wanting things, frequent task switching, adjustments, unnecesary additional steps and minor decisions etc. It can make you feel more energetic in the sense of being "activated" but it's not as agitated as in anxiety. One of the very few similarities might be more intense stimming to let off the energy, but imo it's a different type of stimming. It's also not a negative mood, there isn't a mood associated with it. Anxiety results from a negative emotional state.
Still learning!!