I have had overwhelming feelings of wanting to quit over the past few months.. the thought just won't leave me and I haven't had any positive feelings towards the PhD for a loooooooooong time. My relationship with my superviser is poor and I don't feel like I can talk to them, even about my work, let alone the fact I am struggling.
The thing is, I want to go into academia (yes, that sounds like a contradiction from all I've just said!!!) and teaching at HE level in particular. I guess quitting a PhD would ruin my chances of ever doing that. Any advice or experience on this?
Another option I am considering is just doing the MPhil - but not sure whether this sort of thing would be frowned upon.

Hi mokey. I'm experiencing something very similar - I'm about 16 months in and I'm really struggling with the PhD (change of topic is making me feel miserable).

Have you tried speaking to an advisor (if you have that system), or have you got access to a confidential academic advisor in the uni - I found that speaking to someone not connected to department or PhD was quite helpful (Even just to get some reassurance that my problems were "real"). I think the question you need to ask yourself is whether you feel you can achieve the PhD (with whatever changes to your routine/supervision may be needed) - could you "put up" with the PhD/supervisor for whatever time you have left? Could you even change supervisor? Like yourself I have a keen interest in academia (particularly clinical psychology) but I'm not sure whether to start a new PhD elsewhere, or whether to just try and get this PhD back on track... Hope things get better!!

My heart goes out to you mokey. I've also been having these thoughts. I would suggest making an appointment with the internal counselling service, as rcd suggested, so you can feel safe in expressing how you're feeling. In most cases, student counselling services are very helpful, and will be very familiar with what you're going through, as they're trained to deal with any issues/problems that students face. I was talking to a friend who works in a postgrad support role at the uni, and he told me that it's quite common for PhD students to get these thoughts about quitting, and at several stages during the PhD. It's not surprising really, we're juggling alot of issues with the PhD, one of which is the feeling of being in solitary confinement for three years!

rcd and bellaz - thanks for your supportive comments, I have had a quick look into the student counselling system at my uni and I think I will make an appointment to see them
With regards to changing supervisor, this is something I will have to give more thought. How easy is it to do this and how much office politics will get in the way? It would be great to hear from anyone who has successfully done this, although it seems quite a daunting thing to even bring up with my superviser in the first place!
Luckily I am only about 6 months in to the PhD, so quitting would not be wasting a huge amount of work (I've done hardly any over the past few months due to these feelings). However, I DO feel like I can do it but I just don't know 'what' it is that I can do, if that makes any sense!! I am also a very shy person, and I have worked myself up over having to do various presentations, and also receiving criticism - I think those are the parts I can't/won't cope with!

whilst I sympathise I think you are approaching this all the wrong way! The MPhil is not the easy route, there is still a major dissertation and viva. If you are overwhelmed that is different to wanting to quit - you need to take control of the research and speaking about your feelings will make you more capable of doing this.
You will get nowhere in academia as a researcher without your PhD - times have changed its entry level qualification now - good luck

mokey,
I sympathise. To answer some of your questions:

It is not the end of the world if you drop out, even if that may appear to be the case. Someone on this site put it well by saying that worse things happen at sea....

I dropped out of my PhD after getting mauled by my supervisor in my first year review. I took my case to my department and they took my side.

I did eventually dropped out but I have since then been offered another PhD position and places on two masters courses at different univerisities. So its all good

Ask yourself: do you enjoy your topic and will obtaining a PhD in this area help you in achieving your career goals. if so then transfering to an Mphil may not be the answer.

if it is just a case that you are recieving inadueqate guidance from your supervisor and/or your working relationship just isnt going to work it may be possible to change supervisor.

people transfering PhD projects and/or supervisor is more common than you might think and this was suggested to me when i was doing my PhD.