ps. sorry that I wrote a book, but I do understand your pain. My mom died too.
You loss your mom at a time where you needed her the most during your teen years to this awful desease that has claimed the lives of so manywonderful people. My nieces aunt on her dad's side was just buried a few months ago. She was in her early 50's and died of breast cancer. My mom died in my arms of congestive heart failure and diabities. Mom suffocated slowly as I watch death steal her from my arms, yet mom was a Christian woman and an example to me of faith in God, until my very last breath. Who are we to judge the Almighty...nobody. I have such great faith in God and He gave me the strenght to survive "7 ", yes, I survived 7 death's in 8 months, which included my mother, brother in law, my fiance's father 2 wks after mom, her best friends who attended her service and burial died 4 months after mom from cancer and my brother loss his first child 2 weeks before Christmas. I loss my job and wedding postpone. God is my strenght and I did go thru a period of anger at him for not saving my mother and I felt like "Job" from the bible being tested to my knees and I'm proud to say, God is my strenght and I will never doubt him again. Mom wouldn't want me to ever lose my faith in God!
Although you were not there when your beautiful mom passed away, death can never take away that bond that you will eternally share with her. She is your mother and death can never take that away from you. You are spiritually bonded eternally!!!! She is no longer suffering with that dreaded desease and she doesn't love you any less, because you were not there at her hour. She was so ill, she didn't know who was there, but her love is eternal...she's only a transition or a prayer away! Also, "ye of little faith" to stop believing in God, especially during this life changing trial. Your faith has been ultimately tested and you walked away from God. Where was your faith to sustain you! I wanted to die when mom died. Many times I have fallen on my knees on top of her grave wailing in grief, yet I felt this unbelievable strength to survive one more day! The wage of original sin is death (Adam and Eve) and we are all going to die, but I rather walk with God in this life, than lose it, because I didn't believe in him. Who are we to judge God, if anything lean on him for strenght, peace and hope in the resurrection. I will see my mom one day and I will live with courage and faith in God and I know I will die one day, but I want to die with strong faith in Him and hope in the resurrection.
As for your father, he didn't want to continue life alone and he had every right to remarry again, because the vows are "til death do us part" and he kept his wedding vows to your mom. I understand how difficult it is to see him move on so quickly, but only he knows the grief and sorrow that he felt after her passing, so if necessary, you must forgive your father if you felt he married to quickly. He is still your father and did obey his marriage vows to your mom and has a right if he chooses to live life again and also be happy as he wants this for you and for you to be a part of this new union.
Also, you have not mistreat your girlfriend who is innocent of your history and shouldn't be mistreated, because of your fears. This is wrong and you are sabotaging your happiness and future with fears that you need to face and talk about your feeling to her. It's time to open your heart and soul to this woman and let her in. Your mom would have wanted you to simply live and be happy, so open your heart to this girl and treat her the way she deserves to be treated, with dignity, respect, trust, love and communication.
There is nothing wrong with you. You are a young man who had the misfortune as myself to losing your mom and it hurts. You miss her, grieve her and struggle being without her. Your mom want you to make her proud and simply live. Live life to the fullest. Start slowly to develope a personal relationship with God, who wants you to go to him free will. Without God you will always have a void, so I recommend that you contact a priest or whatever religious denomination you were in the past and tell him how hurt and angry you are at God and he will be more than happy to listen, understand and help you answer some questions, such as I did, "why did my mother have to die," "Why did God take my mom,", "where was he when my mom was dying,". God is a prayer away. Good Luck.
I know exactly what you are going through my mother also had lung cancer that spread to her brain the hardest thing I have ever & because of that my life will never be the same again.You have to be able to live life surrounded by love or will life really be worth it? Also believe in God & one day you will see your mother again in a place where there will be no more sickness & pain.
I know how much it hurts I cant bear to even think about the days my mom was sick & sometimes I just try to block memories out completly cause it hurts that much.Please look to God & he will guide you through one day at a time.
Blessings
Lisa