I am in a serious dilemma right now with my PhD. Here is a summary of my problem (academic only)
1) My project has been changed a year ago, and until now there is hardly any consistency in results and the direction is still uncertain.
The data I've generated I don't think are publishable and I'm virtually stuck in a spiral of no results - no direction - go back and re-do - no results - and etc.
2) I am getting limited support from my peers and others on the project
3) I had a project of my own when I joined the lab, was asked to change it and I find it hard to relate to any of my interests. I don't hate the project by without a clear direction I can't seem to find myself even liking the project.
4) I fear my supervisor who's going to get upset and angry when I tell him how I really feel.

My funding is limited during the phD course, hence no extension.

I am not asking whether I should quit / continue (because I'm not going to quit), but just to find out whether there's anyone here who is facing / has been through similar crisis at the later part of the PhD and what are the ways to get out of this depressing situation.

Yes. Me.

I always feel like this and find it helpful to re-cap what you have achieved. I always forget one of my chapters is on a protein I found does not do what it's predicted to. That's not massively exciting but it's a result and it's a 'contribution' to the field, albeit a small one.

As for the rest of my work, I remind myself I've done loads of work so far and I'm just falling at the last hurdles. It'll be deeply unsatisfactory to me to finish without the results I want but I'll probably still pass. The 'end point' in my RCUK funded PhD is pretty arbitrary and to not have the perfect, finished project by the end is not a mark of failure.

Sounds like me. My first year was rather unproductive due to refining of directions and in my second year, my proposed direction and works went completely out the window (ie lost A LOT OF TIME). How this happened and how my supervisors behave are another long story, but the point is I had not much data at the start of my third year. And yes, I was very depressed, and I wanted to quit because it seemed hopeless but as it meant losing my scholarship, I held on. Quickly I did some searching to see how I could rescue my project. I am now in my last few months, still no paper, but dragging myself to the finishing line. My goal now is to finish as best I can with hopefully a PhD. It is quite a significant change to my initial goal of having X papers and finding X scientific outcomes, but finish is better than not.

In your case, can you first talk to your supervisors about your thoughts on this? Remember, he may be upset, angry, etc, if you tell him, but YOU will be upset, angry, etc if you do not cross the finishing line. It is YOUR future. Your supervisors have already forged their future and you are one small student in a long line of students they will have in their career. If they do not want or cannot help you, talk to your thesis reviewer/committee, head of school, etc to rope someone in who knows the field. Your silence will NOT help you. Also, maybe you can talk to your uni counsellor if you need to sort out your depression/feelings. So, my advice to you - find the courage and talk to someone. You still have time to salvage the situation. Sending you positive vibes ~~~