Hi,
First of all, I completely agree with everything in the other comments. I'm about to head into the third year of my PhD and have my annual review coming up in a couple of days and I feel hideously, heart-stoppingly anxious about it at the moment! I will say from experience that, even though I'm feeling terrible at the moment, by the time my review is over at the end of the week, I will probably be feeling fine again - a PhD is all ups and downs so I can't say that everything will always be alright but I can say that the lows won't last forever, even if sometimes it feels like they will.
Definitely talk to your supervisors about your depression, I didn't want to talk to mine about my anxiety and depression issues at first (for the same reasons as the others in this chat) but I realised soon into my PhD that I had to and it was the best decision I could have made. My issues have not gone away but at least my supervisors are aware and it allows them the opportunity to step up and support me, without which I could not have gotten through to this point. Many of us, in fact I would go so far as to most of us, experience these feelings during a PhD and it is not a reflection on you or your abilities whatsoever. It's a hard system and I still think about quitting but I'm so far into now that I feel like I have to do my best to carry on, a PhD is more a test of endurance than intelligence or anything else. Sometimes it can be helpful to read example theses online (I use ethos) to see what quality a thesis needs to be to pass as many of them are not actually all that good, it's just so built into us that it must be original that it makes the whole thing feel like an impossible task.
I had my first year review last year and it was a harrowing experience, though I still passed it. It is not uncommon to get harsh comments - unlike undergrad or masters, I think we're seen (perhaps unfairly I might add) as being able to cope with the criticism at this stage of study and, in my opinion, I think reviewers often feel like they are doing the student a favour by laying out every deficiency, even if it feels like they are picking your soul apart! They wouldn't have passed you if they didn't see your potential. I was always a straight A student and so the transition to PhD study was the hardest thing I've ever had to manage as suddenly I went from being one of the best to consistently feeling like a fool, like an imposter and a failure - I only say this because it sounds like you feel similarly so I want you to know that you are absolutely not a fool, an imposter or a failure. You can get through this and, if you decide that you don't want to put yourself through it, it is only a PhD at the end of the day, it is not your life or your entire future so don't let it rule your entire existence or take over your sense of self-worth.
With love from,
A Fellow PhD Sufferer x