I can only speak for what I've experienced...
There are different levels, much like depression.
Sometimes, it is merely hard to smile. Other times, it's hard to move, at all.
You might find that you can still stand up and get on with your day.
Then again, you might find yourself alone in the dark, on the bathroom floor, covered only with a towel, crying for much longer than you want to admit, because it hurts that bad. Crying for a million reasons (that continuously ricochet in your head like small metal pellets, doing absolutely no good whatsoever), but it's mostly because you fear that you are too much and not enough.
Not only am I learning who I am (and how to be okay with who I am), but I'm learning to feel through vulnerability. Living is amazing, to say the least, but it is hard and scary feeling with clarity after so many years of feeling through murk.
Everything, the good and bad, is magnified. I imagine it would be like someone who was color blind, seeing colors for the first time. Except that's the nice way to see it. You might also compare it to the difference between a needle pricking your finger and a dagger through the gut. The good is out of this world, but so is the bad.
So, with vulnerability has come subpression. And the best advice I have thus far, if you happen to find yourself in the mist or downpour of it, is to let yourself cry and (no matter how painful you might think it will be) continue to do things that feed your submission, do it because it makes you feel good. You already have enough reasons to beat yourself up, don't go throwing more on the plate.
So, yeah, subpression. It's real and it sucks.