My face starts looking dull ansd dark once i go out??

Ok so this doesn't always happend and at this point I am not sure if it's real or I am just imagining it but i've noticed that sometimes i would wake up with the most fresh and bright skin ever than once i step out and look at my face in the mirror i look like a totaly different person my face looks so dark dull full of imperfections i didnt know even existed like tf ? If anyone experienced smth like this before pls help