concertration

i cannot concentrate on my studies,  i do not know what to do to rember things, i feel tierd and lazy all the time

[Roger Gould, M.D.]

I will give you the same advice I just gave for a similar problem...when you can't concentrate,it means you mind is "elsewhere", your mental energy being used to suppress the other problems, and your brain is telling you to face and deal with these issues...that is the best way to regain your concentration......either see a therapist or do it on your own with the help of new website...www.myvirtualshrink.com...it is a self help alternative to therapy.

[Jaquta]

Perhaps see your family doctor to rule out any medical problem.
Being tired will affect your ability to concentrate and remember.  Try and get adequate sleep.  Also make sure you take regular breaks from study.  I heard that after about 50 minutes we start to retain less information.  Do some study, take a break, then come back.  Maybe even take an extended break if you're stressed to the point where it is interfering with your study.
What has worked for you in the past?  Could you try some of those techniques?
If the study is becoming too much you could try and break it down into more manageable chunks.  Smaller goals may help you achieve the bigger ones.
Perhaps you could also take the focus away from the result (if that's what's stressing you) and put it on exam techniques, etc.
Maybe even going through some of the material with a friend, etc may help.
I think it is often better to have an understanding of the material rather just memorizing it and regurgitating it (which is something I use to do).  Just keep it simple.

Good luck with everything.  Confidence in yourself and your ability goes a long way too.