Dorselm,
Please don't ever lose your empathy and compassion! It is easy to get burnt out in the world of nursing but I can tell you that you will be remembered more for the little moments of caring that you show to your pts and their families than for any amount of booklearning.
If you treat every patient that you have as if you are looking after them in their last moments of life the way you did for that gentleman you should never have any regrets about your care.
Your first pt death is always hard. I'm sorry you didn't seem to get the support that you needed.
Just keep up the good work and remember that making someone in his situation feel even more slightly comfortable and cared for has immeasurable value. Kudos.
Gypsy