Get the meds. Take them, if prescribed. They won't fix the problem, but they can help you thru the worst of it until things become a bit easier to deal with. I wound up weaning myself off of them (I don't recommend that, btw). For some people, they are long-term, but personally, I found it to be a bit too long-term.
The biggest thing, and the hardest, is to be honest with your friends about it. I've told friends I have problems with depression. Turns out, another friend of mine does, too, and we try to help keep the other on an even-er keel. I told my boss and my relatives. They know that if they don't hear from me in a while, to come over and kick in the door or do what's necessary to drag me out into the light.
Know this: you're going to have bad days and worse days and some good days. Pay attention and you'll be able to recognize them for what they are and when you need help.
But get help. I've had to deal with everything from being unable to leave the house or turn on a light to irrational exuberance, on top of a couple of other medical issues. I'm nowhere near cured, but I'm not down in a hole anymore.
It's survivable and your life doesn't have to suck.
Can attest. Can absolutely attest to this.
For some reason there can be a stigma around that profession but PLEASE don't let that deter you, as it will be tremendously helpful. They can help you see your true self when things seem cloudy.
And a note to deathbysw123: I too really recommend finding a therapist. I used to think that if I was smart enough I could figure this stuff out on my own, and that pride kept me from getting help. But a therapist has two advantages: they have seen a zillion people, and so have raw data for pattern-finding that you don't, and they are outside your skull, giving them a perspective you can't have.
https://www.castleconnolly.com/
There is a small fee, although you can still see the doctor's name and location without joining.
The author must have forwarded my email to a colleague (who may have, in turn, forwarded it to further links in a chain - all the intermediary addresses were duly absent from the final referral I got, as should be expected from professionals), because soon after, I got a response from a new contact, referring me to a therapist who turned out to be a good fit.
Looking for a therapist can really suck (I'd had somewhere around eight months of trying at least five different bad-fit therapists before I tried the random-midnight-email approach above), so I figured I'd mention the approach that actually ended up working for me.
The worst part of depression is that it clouds normal thought processes. That's probably why you can't perform as you once did.
Find a way to see a psychiatrist you feel comfortable around. Go with a family or friend if that helps get you over the hump.
So many high achievers I know go through this. You're not alone, and with proper help you'll get through it, and be stronger too.