While I always promote being grateful for what you have and working through life's problems, it is also necessary acknowledge your problems as important to you. While it is true that someone always has it worse than you, it does not mean that your problems and issues aren't critical relative to your life. It is ok to be upset and allow yourself to grieve. It is possible to do this and be grateful at the same time. Take your problems in life seriously, even if others don't.