当感到需要休息时，用英语可以表达为以下几种方式：
- I need a rest.
- I feel like I need to take a break.
- I’m ready for a rest.
- I’m tired and need some rest.
- I think it’s time for a break.
- I’m in need of some rest.
- I’m feeling exhausted and need to take it easy.
这些表达都很自然，可以根据具体情境和语境选择最合适的一种。