Merhaba

The phrase "merat etme" means don´t worry. dogru mu? Is this just a simple way to generally say dont worry? Are there any other phrases? I sometimes use sorun yok.Is that the same?

Sorun yok --> No problem.

Don´t worry  ---> Endişelenme! Merak etme! Dert etme!

It also depends on  your level of  worry. 

I mean, if your worry makes you sad then you can also say " üzülme " .

Tunci ,yardimin icin tesekkur ederim