How can this happen?

Not posted for a while. Quick run down.

26th November 2015- My Gran passed away to brain tumours.

27th February 2016- My Nanna passed away to lung cancer.

21st September 2017- My Mum passed away to lung cancer and brain tumours.

19th August 2018- My Grandad passed away to lung cancer and 2 heart conditions (totally unknown and unexpected)

I have my Aunty, my Uncle and my Dad. Me and my Dad aren't really on great terms at the minute due to a personal reason.

I'm only 21. How is this fair? Who's next out of my 3 relatives that are left? 

I tried counselling years ago and hated it. I don't know what i'm meant to do, i feel like i can't turn to anybody. Anybody who says anything to me to try and console me i just get angry at. Not literally because i'm not that awful but in my head i'm just thinking 'you have no clue, no idea, just stop and shut up'.