God has NOT abandoned you, hun, trust me. You're his little girl and He will always be there for you. Make sure you keep praying, He knows what you need, but loves loves LOVES to hear from you. This experience you're going through right now is going to make you so very strong. Suffering tries and tests people, purifies
their faith, corrects their flaws, and refines their character. What you're going through is actually an expression of grace and love from God in disguise because once people have come out of hard times and accepted correction, they will shine with a tested and confirmed faith and a splendid character. Especially if God chooses you to do special work in the future or help someone in the same situation as you. You're going to learn so much from your hardships, and nine times out of ten, something amazing comes from your experience.
Some verses to check out:
"We rejoice in our sufferings, knowing that suffering produces endurance, and endurance produces character, and character produces hope, and hope does not disappoint us, because God's love has been poured into our hearts."
-Romans 5.3-5
"I will put this third into the fire, and refine them as one refines silver, and test them as gold is tested."
-Zechariah 13.9
Here's a story to help you understand:
Hard times are like a refining fire: A wedding ring starts out as yucky looking, mess of minerals, basically unpure-gold is: alloy, silver, lead, copper, iron, bismuth, traces of platinum and palladium, and frequently a small percentage of iridium. The gold needs to go through a process of treating and cleaning called refining in order to be pure, beautiful and strong, and be the best it can be. First, the main minerals need to be sorted out by means of sulphuric acid, then wind-furnace and stone-coal fire. A special oxidizing chemical is added, and then everything is heated to a bright red molten lava and stirred. After it's poured into a bar mold and cooled, the mixture is hammered smooth and chipped and sanded. Sometimes there is still lead in the gold, and they have to remelt it and begin the process over again to get it right. Once the gold is perfect, the ring maker designs the perfect look for it, creates it, adds in beautiful precious stones and diamonds, polishes it and it's ready. Perfect, and for the buying.
The same goes with all of us. We're not perfect, but through trusting God, we can learn to be more like Him. Don't give up, stay strong. Your sister needs you. Pray, and endure the fire.