Sometimes it feels like being "higher functioning" is a lie. Those of us considered "high functioning" may or may not experience "severe" symptoms but it's how we cope and deal with them that gives us this lofty title. Those who aren't often say the phrasing as though it excuses away what we experience, minimizes them. When we have good days, the ones with minimal or even no symptoms, these are what are considered our baselines by so many and then our normal is considered "bad days" and heaven(s) forbid we have an actual episode because then we get the looks of "now you're just faking it, I've seen you when you're not doing well"...
I don't feel like I'm "functioning"... I feel like I'm merely existing most of the time. I sit at my desk or even in the field struggling to focus half the day and trying to use deep breathing exercises. Most of the time I'm losing approximately half my day worthy of productivity to "coping". Luckily, I'm still productive enough that it's not so noticeable, or so I think, so I hope because I love my job and do not want to lose it... But this doesn't feel like functioning.
However, if I were to go to someone and say "hey, so, I feel like crying, screaming, laughing, passing out, painting a picture, pulling my hair out (literally not figuratively), and curling up into a corner staring at nothing and everything all at this exact moment" I am not likely to be believed because I "look fine". This is Fine.