sorry maybe im asking something stupid but i have no idea .... do turkish people celebrate valentines day?? and if yes what do they say  for ´´happy valentines day´´ to the one they love??

 There is a word for it........

´Sevgililer Günü´

niceeee thanksss ... and what means that???

yes, they are celebrating; last year I was in Istanbul in february and I saw In Olivium center (a big outlet mall) decorations of Valentine`s day 

and I found these on google

http://www.learningpracticalturkish.com/turkish-terms-of-endearment-se.html

the day of lovers

 It means ´lovers day´

 Sorry elanagabriela, I didn´t see yours, you got there first

the simplest way to say this is:

"Sevgililer Günümüz kutlu olsun aşkım (or canım, bebeğim, bir tanem)...

not problem canım benim, you are wellcome

..it sounds so romantic....better like in english (my point of view)