My job

Sometimes I think I have the best job in the world but at other times I would like to have a different job.
I work as a nurse in the critical care unit. Although it is exciting, at times it can also be very stressful.
I have been working in this unit since 2005.  It is a challenging job that requires me to continue learning new things on a daily basis.  I believe that nobody should work in a critical care unit for too long because it can drive you crazy.
Eventhough I love being a nurse, last night I was working and thought that the moment to leave critical care is coming......not yet.....but in a few years or months..... who knows??

We will see....

My job

Sometimes I think that I have the best job in the world but  another other times I would like to have a different job.
I´m a nurse and now I´m working in a critical care unit. It might be exciting many times Often it can be exciting but if you have so too much excitation excitement it can became stressful. 
I have been working in this unit since 2005 and every day there are new things to learn. But (you should never begin a sentence in English with but or and) However, I do believe that no one should be working in a critical care unit for many years because it can drive you crazy.
I love being a nurse. However, yesterday last night while I was working and I began to think thought that the moment time to leave critical care is coming......not yet.....but in a few years or months..... who knows??

We will see....

Very well done and your English is excellent!!  Just a few minor changes to give your post sound more polished, but I stress that these changes are quite minor.  See if you notice a difference when reading it.  I look forward to seeing more from you here on italki!