Update ~ Sending my son to live with his dad

So without getting all the way into it I made the decision to send my almost 13 year old son to live in Oklahoma with his dad. He has adhd and behavioral issues and things have just gotten so bad. We fight every night, he's disrespectful, refuses to do his homework. You name it. I have tried everything I can think of discipline wise and nothing is getting through to him. I finally told him I was thinking about sending him to live with his dad for awhile as I am 8 months pregnant, have a 1 year old and have a history of preterm labor and I don't need a houseful of stress. Even with all of the stress, I am torn up about it all. I feel like someone is ripping my heart from my body. I was a single mom for a long time and I really don't know how to exist without him here with me. I guess I just want to know if anyone else has had to do this and if it was a positive experience. He doesn't know his dad too much. He left when my son was 1 1/2 and we have seen him only a handful of times since and talked on the phone. He is so excited to get to know his dad and I'm glad for that but I don't know how I'm gonna put my baby in that car tomorrow and watch him drive 8 hours away. 😢