Non ti preoccupare
I understand that NON TI PREOCCUPARE means DONT WORRY YOURSELF, however i have been told that to say I DONT WORRY is NON MI PREOCCUPO! Is there a difference if I said NON MI PREOCCUPARE to mean I DONT WORRY or does this change to DONT WORRY MYSELF...however this is has the same meaning in English, please help?

Question

Answer

It's because NON TI PREOCCUPARE is a command, is imperativo in Italian, which is why I cannot say a command to myself, so we don't say NON MI PREOCCUPARE.

the present tense as in statement is:
IO NON MI PREOCCUPO
TU NON TI PREOCCUPI

Answer

We never use the form /non mi preoccupare/, the only form we use with /io/  is:
-- [io] non mi preoccupo, (/io/ is optional)
or (with TU) :
- non ti preoccupare 
- - non preoccuparti
(exactly the same meaning!)