Yes, God understands your feelings. He also knows all about your background and why it's so hard for you to trust anyone - including God.
But God also loves you, and He wants to help you overcome your feelings and discover the joy of trusting Him with your life and your problems. He doesn't want you to go through life with this burden of mistrust (and whatever else is crushing you from the past, such as anger or hopelessness). Instead, He wants to take away this burden - and He will, if you will let Him. Jesus said, "Come to me, all you who are weary and burdened, and I will give you rest" (Matthew 11:28). This invitation is for you.
People may disappoint you - but God never will. God's love doesn't shift and fade (as human love often does); His love is constant and unchanging. How do we know His love is this strong? We know it because He was willing to send His Son into the world to die for our sins. God loves us this much! The Bible says, "This is love: not that we loved God, but that he loved us and sent his Son as an atoning sacrifice for our sins" (1 John 4:10).
Begin by trusting Christ for your eternal salvation and committing your life to Him. Then let your prayer each day be like that of the father who came to Jesus on one occasion: "I do believe; help me overcome my unbelief!" (Mark 9:24).