I'm a PhD student and writing the final chapter of my thesis. I need to Rant...

I've found myself reflecting over choices and experiences during the writing process and I can only conclude that I'm incredibly disappointed in my supervisors and academic institute. They have failed me.
I have 3 supervisors (S1,S2, S3)and only S2 (most removed from the research) has actually taken an interest. However S2 bullied my for a year, drove me into depression which forced me to start counselling and now i have a therapist. Side note S1 forgot I was his student so that was a fun conversation.
I realised for all supervisors involved my PhD was the "side project" and no one really had a clue what was going on. All the projects I was given were pointless not publishable, all the projects I came up either didn't work or they wouldn't let me pursue. I've spent my whole PhD with the attitude "I need to salvage this".
I finally found a niche, and the only reason I published two papers was because I went against what I was being told to do and actually found an interesting angle. During the process of writing both papers S1 asked "Why is this interesting again?"
The only encouragement I have had has been when I've gone to external conferences, had feed back from reviewers and an examiner during one of my PhD milestones.
Now I find out the research project I planned has been given to another student by S1 despite all the hours I spent preparing the lab reading literature and doing the background work.
A PhD shouldn't be like this. I have achieved some awesome results and physics and yet I've had zero support. This experience has diminished my passion for the culture if not the subject.
I cannot recommend a PhD at this institute to anyone.
When should a person say enough is enough, this isn't for me and just walk away?
How do we ensure we get the right support?

I am so sorry that is sound insane, but day after day not only you and me, there are many other students suffers. I don't know which country you are in? However, if I were in my shoes, I would go directly to the supervisor and speak to him in an honest and respectable manner, you must make sure to avoid the emotions, because I know that sounds savage and insane. This is your work and your efforts, be smart enough to convince them and there is no problem if the other student cooperates with you and publish together, you spent many years, and you must fight for yourself in a smart way and get your soul all out of this mess.

I wish you can manage that as soon as possible, good luck.

Projects can be handed off because you no longer have the time to start/complete the new line of research, and also because it can secure further funding for the dept. Don't take that to heart.

If you have to published papers you have more than some PhD holders. Just push forward with your write up, submit and move on to a better project/department/career. You've earned it after years of work.

Thanks everyone.
I'm really glad with what I've accomplished, but I'm clearly a bit bitter. And i know so many students have had it worse. I'm really lucky I found a niche.
But because I spent so long floundering I've spent the last 5 months unfunded writing up. Not only that, I do have publishable content in my thesis yet there is no funding in my department to keep me and myself and supervisors know I'll certainly publish it cause it's in my benefit to do so. S1 has jumped ship (I'm in the UK and Brexit has seen mass exodus of non-British academics) and taken all his non British students/postdocs to mainland Europe.
I've got a new research job lined, in a very different field and institution (i wonder why I'm not staying!). I'm sad I'm leaving all the work that I built from the ground up, excited and terrified of moving to a different research field with limited experience.

Kikothedog, I understand projects can be handed off, but it feels like S1 is taking my IP, jumping ship and stabbing me in the back. He already neglected to acknowledge myself and a colleague as coauthors/acknowledgements in work where we fabricated the samples. One part of me wants to talk to him about this and the other wants to just walk away and be done with this experience. But this idea was what I wanted to do for my PhD in the first place!

Monika, I'll try and talk to S1. Even if I'm at different institute, I'm still the only one in my department with the most experience working with this material and understanding how it works. I'll try and put my emotions on hold.

I sometimes wonder if I've been incredibly stubborn and pigheaded to have lasted as long as I have. Not sure those are good qualities to have...
Thanks guys