Hi all,
I completed my UG in 2004, did a Masters in 2006 and worked in a different field for a couple of years. I got accepted for a Phd program in November with full sponsorship. However, i already feel frustrated, depressed and de-motivated. The reason for this are two-fold:
1. I do not have a good grasp of programming...... which is a core requirement for my program.
2.I also feel lost about basic concepts ....i have to refer to materials which i used in my first and second degrees.
This makes me feel like i cannot complete the Phd. I feel the urge to quit most times.

I have discussed these issues with my supervisor, She assures me i am making good progress based on our discussions and i should not be worried.However, i cannot help being worried She also tells me as soon as she feels i am not making good progress, she will let me know. I feel like quitting now rather than waiting for the -inevitable - day. Quitting also means paying back a large chunk of money that my sponsors have expended on me. And how do i even explain it to my family? I really want to shoulder on but i feel i am just postponing the inevitable.
This has made me to have sleepless nights and as result i have lost so much weight.
I really feel lost!!!

The oroblem here is that your expectation levels are way too high.
You should expect to take around a year to learn enough to be competent.
Learning a programming language competently and sustainably alone will take about a month or two.
You have only been going a couple of months.
Listen to your supervisor.

Absolutely listen to your supervisor - I bet you are doing fine, academically.

I am in my second semester of PhD study; last term, I thought I was absolutely terrible. Went into every supervision expecting to be told that my work wasn't up to scratch, my supervisors didn't think I was cut out for it, and that I should just go for an MPhil and be done with it. Went home over Christmas thinking about quitting.

Needless to say, none of that ever happened. I am still not super confident, but this semester something has just 'clicked' where I feel like I'm at least on track. You're struggling with impostor syndrome - mine was pretty acute for a while, and has lessened now, but some people struggle with it throughout the entirety of their PhD. It can at least be managed and is totally normal.

The key thing (as I have been advised by other PhD students who are close to completing) is to just get out of bed each day. Keep putting one foot in front of the other, turning up, and trying. Eventually, it will click; even if you go through your whole first year feeling confused and clueless, that's not necessarily an indication that you're doing poorly.

Supervisors have no interest in sugar-coating their assessments of you; if you're doing poorly, rest assured you will absolutely know about it. Assuming they've supervised before, they know the process, they know where they expect you to be and what you're experiencing. You have to trust their judgement at this early stage that you will be OK.

Don't give up; you've done amazingly well to get a sponsored PhD, and have been judged competent by your funders and your supervisor. It will get better - just keep going, and give yourself a break. If you're losing weight, I'd really urge you to go and see a campus counsellor or therapist too. This is not worth destroying your health over. Good luck.

I agree with what is being said, and I'm in a similar situation in that I don't have a good grasp of the methods I need for my PhD - But I chose those PhD because they were methods that I wanted to learn. I could have chosen a PhD which just used methods I've been using in my work since I did my undergrad in 2006 but ultimately, what would I get out of that? Isn't that a waste of a PhD.

Why are you angry at yourself for having to refer and look up things you did over 10 years ago? Everyone forgets things they haven't done recently and needs reminders.

There is nothing wrong with being pushed out of your comfort zone, I completely get that it is daunting and I too worry that I'm not doing enough or I don't understand things I should, or the worst, I'm not explaining myself well enough. I've been having ups and downs since I started... This week is a down for me too.

Keep your head down, don't punish yourself if you don't understand things straight away, set small goals. Reward yourself.

You'll get there. I'll get there. I'm sure of it.

@chantedsnicker....that was a best comfort words i have not read for decades. Brilliant advise for sure. I am almost going through of what Alpha-Jay explain. I am in my first year, and i got a feedback from supervisor after submitting my first draft of literature review. His comments was " your draft is not yet in PhD level". I felt like may be this is not my place..... I am a parent, full-time employed etc....but what i came to realize is that quiting is not a solution! Each day build confidence and determination that, I CAN, I CAN DO IT.