I
have been meditating for some time and feel quite peaceful,
but other times I cannot settle-down. Is this abnormal?
No. Sometimes
we can have 'off' days: there are many different conditions
that affect meditation, for example food, social activity, your
level of self-discipline [see ?3.3] and your feelings of success
or failure. Sometimes you may be put off meditation by physical
conditions beyond your control such as magnetic fields or atmospheric
changes. All I can suggest is to keep on trying and never be
disappointed about any session you practise.