Long story short, 6 years ago I started a PhD in plant pathology and it's gone downhill. Before that I did my Master thesis in the same lab, which I barely finished. One main issue is that I was stupid and shy enough to store my cultures in a way they degenerated rapidly. I feared asking how to do it, since I was having difficulties even back then. Instead of preparing a conidial suspension and storing it at -80C without thawing I had prepared mycelial stock which I repeatedly thawed, not knowing it was a wrong thing to do. Later, I tried preparing agar plug in 25% glycerol and store in it fridge but the viability decreased rapidly after a year or so. I did that repeatedly so now I'm left with a few degenerated isolates which do not sporulate and only grow as a white mycelium.

Because of constant stress due to other issues I did constant mistakes in my work. Eventually my supervisor had to slightly change my subject as I was wasting lab consumables (enzymes, buffers etc) without any result. Now I'm a 38 year old nervous wreck, have never worked and have no idea whatsoever what to do in my life. Also, because I was (and am) so stupid and self destructive I still haven't told my supervisor about my issues thinking he would tell me to stop my PhD.

Basically I've done everything I could to waste 5-6 years (actually more) of my life doing just about nothing and make myself fail my PhD. To top it of because of my stress I've destroyed my health. I knew this would happen.
So the question is: what do I do now? I don't have any idea what to do. Heck, I don't know if I even like my profession anymore. I guess start networking, search for jobs (zero confidence, everything is down the drain). The only jobs I can think of is menial ones.

Props do anybody who read until this point.
Please advice.

You can always start again. Just start something that you feel motivated to do.

Ok. Your situation is not ideal but at least you acknowledge where the problems lie.

Regarding your PhD, I suggest that you own up and tell your supervisor the truth. Tell him that you were too shy to ask for help and as a result you stored your cultures in the wrong manner and that has big impact on your work. And discuss about what you can do next. He may ask you to write up and go, or he can come up with emergency plans to set things right. Telling him will also release some of the stress you are under because you no longer have to hide the problem.

Regarding your other stresses, I suggest that you go to the counsellor. Talk to someone and ask for help and support. You need them. You have identified that your shyness, reluctance to ask for help and low self esteem as problems. If you do not sort them out, they will repeat in whatever setting you are in future, academia or not. Let the counsellor help you out.

Regarding a job, I suggest that despite whatever the outcome of your discussion with your supervisor, you should take a break for a few weeks. It has been a diffiult 6 years and a break would do you good while you find yourself again. Then start looking. You should discuss with the counsellor the types of job that may be a good fit to your personality amd find joy in life again.