Why do people keep telling me god is kept me here for a reason?

I'm a good person, I feel the world's pain, I would give you the shirt off my back if you needed it, I let my mom have custody my son when I didn't need her help because my family convinced me I needed to for once in my life let them help me because "I shouldn't have to do everything all alone" and that "that's what family's for" I promised myself my son would never have to go thru what I have been thru with my family but I thought They were sincere. They passed my son around like an unwanted puppy. Each one playing the part of a good uncle, aunt, grandpa, grandma, I was doing everything right, I was managing my PTSD, my depression, taking substance abuse classes 3xs a week, drug testing 3xs a week, therapy sessions for my son and myself twice a week, my son and I had 3-3 hour visits a week and I was working to maintain a steady stable home for my boy but I let my mother convince me I should give her custody because cps is bad and he needed to be with family. So I did. I didn't know I was signing over my rights to my son. She decided never mind I don't want him he deserves a better family she said. She gave my son to cps. She had a job offer she couldn't refuse. I had 3 more visits with my son. I broke. My son broke. I wanna die Everytime I think of the day I let them take him from me. I WAS A GOOD MOTHER. I was doing everything I could to be the best mother. Why didn't anyone tell me that stupid piece of paper was all my rights to MY BOY. How could she do that can to her own flesh and blood? I have no idea where my son is or who he's with. Us he safe and healthy? Does he know that everyday I pray he will find me bcuz I can't find him. What if he gets hurt or dies I'm suppose to be there. Am I gonna go to hell for not forgiving her because I hate her. I've tried to kill myself but God keeps bringing me back. Everyone keeps saying God has better plans for me. Please someone anyone help me understand what the hell that's suppose to mean?