Best case – It feels like nothing, but I notice that work is getting done and that I am not interrupting people mid-sentence or doing other things to annoy them.
More typical – Like above, but I have less personality (the good and bad parts) and are more task focused.
Over medicated – I feel like a zombie and/or my pulse is racing. This was from when I was titrating the dose or forgot that I already took a pill and took another. Please discuss this option with a medical doctor so that you are safe if it happens.
I always recommend that you time tasks that you typically do and have a handle on.
When I am medicated, I am consistently 6 times more productive (literally one hour to do what takes me 6 when unmedicated) whether I “feel” it working or not.