Why

Why hurt me so bad by doing something to me that hurts so bad? I never thought that it would happen so I tried my best to avoid the pain. They say the things you do to hurt someone come back to bite you in the ass, well this really bit me hard. Its like a knife was stabbed in my back in the beginning, and now its getting shoved further and further into my back. Why is it suppose to be that way. Aren't we allowed chances to redeem ourself and stop the bad things from happening? But if things never progress, we never learn from our mistakes! Maybe its good to reap what you sew. Somebody tell me something?