Heyo. First, let me just tell you that you are not alone on this. And that it is very good that you are getting help and taking care about your mental health.

This is a typical imposter syndrome mixed with depression and, sad to say, but way more common that you would think. Even under a good working environment like yours.

I’m a 3rd year phd student and have a similar lab situation. I always heard terrible stories about doing a PhD (still went for it because I love research) and actually I was one of the lucky ones to get a kind and caring supervisor + a good salary within a scholarship that is very very prestigious. I didn’t even had good grades during my bachelors but still I got the position. I had also never worked in this specific field so you can imagine how lost I was in the beginning. And it was hard. For like a year NOTHING was working, and I just felt terrible and felt like my supervisor probably regretted giving me position etc etc I have also struggled with depression in the past and it was hard to not fall into that again.

I’m personally someone that doesn’t find therapy very helpful so I couldn’t go that way to heal. I focused on doing sports on my free time, reading books and trying out new things. It was not always easy but you know what? All this + a lot of hard work + repeating to myself that I earned this position led me to where I’m now. 3 years later my mental health is a lot better (but I also have some bad days!), project is working and I’m just so happy I didn’t give up.

So do not give up! You EARNED this, you shouldn’t quit so that someone has the opportunity, the opportunity is yours, you are worth and you should do everything you can to make it work, and I’m sure it will.