How can you know God is one? When you know that the good times were His mercy, the Bad Times were His tests or reminders and whatever you have now is His will. And when this is your reality, then your personality is such: You do not complain about people, you never curse anyone, blame anyone. You never waste time dwelling on the negative or getting too happy about the positive. Your smile becomes real and your presence stable. You view things , situations and people more deeply and you are so much more forgiving and understanding. You are also smarter and you become the best fighter in the world, the one that never has to fight. Your level of stress goes down substantially, and you never get bored. You feel a quiet and serene joy in your heart most of the time and you enjoy little pleasures and moments.
When you are like this, life is very different with you. Your life will be blissful and you will inspire people and you will bring joy to lives. When you know God is One in this way, then your desires and wants, your questions and your complaints and all that you feel, you will present to Him. You will pray and you will seek His guidance - for when he tests you, you will seek forgiveness from Him, and when He gives you joy, you will thank Him - and when you are sick, you will seek His mercy and soon you will love Him so you will seek to please Him by taking care of His creatures - so your soul will connect to the whole universe to the hearts of all people. You will be a MOMIN. A Believer.
" And worry not , and fear not you are the Superior IF you are grateful and a Momin" This is God's promise in the Quran.
Try to stop the blame game and try and submit to the Creator. Life WILL change for the better.