Yes - there is something that can cause negative thoughts on a regular basis: simply you and your fears.
This might sound hard to you. So let me try to explain what I want to explain to you.
For some reason you picked up the thoughts of people around you, may be from your parents, relatives, friends or whoever who told you that the world is full of unpleasant events like death, robbing, funerals etc. and you subconsciously mind accepted this as 'true'. Now your thoughts are circling around these arguments as you feared them.
Try for yourself to get a different view and with that different thoughts: Death takes part of our life. The person who's gone forever has fulfilled his task on earth. We know that there is no law which will give us an eternal life.
"Being robbed" - you should feel sorry for this person, unable to understand that steeling does not mean a respectful together. Instead of judging him/her try to see him/her on a lower level of education and therefore he/she cannot be punished. Send him/her love and all your positive thoughts to stop steeling.