I know everyone is gonna tell me I'm a terrible sister... I would have helped if I could...

She called me telling me DHS is taking her baby away and she needs me to come get her or they are putting her in foster care. My niece is 15 months. I did think about it I really did, but I have a special needs preteen. He is non verbal. Not potty trained, and he takes up all of my time. My husband works 80 hours a week so he wouldn't be able to take care of her. My son has me on my feet all day, especially with trying to keep track of his medications and therapies. There isn't a way I could take care of a toddler also. I mean she's met my son and she can't even deal with him for more than an hour or so. I told her and she reminded me of when we were in foster care and how she got molested and asked if I wanted that for her daughter. I started crying saying no I didn't, but I have a special needs child who takes up all my time and my husband works so much. She said "Well when my daughter goes through some severe trauma, she will have you to thank for that." I would never want my niece to go through something awful and if I could I truly would. But taking care of a toddler and a special needs preteen, I would end up accidentally neglecting one or the other. I feel like I've been a horrible sister and auntie...