I feared about my thinkings. Need help!

My elder sister was death by hanging 5 months back . After that incident i suddenly getting angry to others , Sun-Times argument with other but there is no reason for my arguement and anger. I have 10 months baby boy . Sometimes I suddenly over tension on him. Now a days I fully feared about nothing , but I'm in fear . Sumedays I dreamed like that my sister telling about something . But that dreams are came true within 2 or 3 days . Some dreams came to finishing in arguement or false . Now a days am also thinking about death . Whats happened after death to people's, where they are going to , why I cannot try this to know ... like that typed thoughts I thinking nd 90% thinking of mine is what to die by hanging and am tried once also . So these sudden changes and that dreams and my thinking are to variety after my sister death . Because I seen his death on spot and I scared also . Don't know what's my problem and why am thinking like this . May b these are all my imagination. Need help