raising a teenager. boy oh boy!!!

I don't know what I'm supposed to do or say anymore. My life is constantly revolving around me. My kids are all I can focus on. I now have a 16 year old who loves me this I know but the constant arguing and daily struggle with him is wearing on my heart and mind. He calls me things like a liar and yells at me, I must admit I often yell at him as well, but truth be told I just don't understand why it is so hard for him to mind. I ask him to do something so simple he makes it a big deal and a two hour argument. The topper he wants to go and live with his dad. I spent his whole life fighting for him and hanging on to him. I remember the moment I gave birth to him, walking in the snow praying the contractions would be enough to deliver him. I remember the breaking words my only son my first born had jaundice. I thought that was the end of the world. Boy was I wrong it was just the start. Latter he began vomiting constantly, and was admitted into the hospital we were told he had interception, which was a blockage, nope they were wrong, we then found he had g.e.r.d's guess what not a big deal right..Yes very much so in his case he was refluxing every 30 mins.He needed a surgery that was not common in children his age. He was only 11 months old and they were planning to tie his stomach valves together to save his life, his body hated food as it kept rejecting it. The surgery was a great success we spent another month in the hospital and he was all better....years Went on and my son was healthy, my marriage was not but I could do this, I was strong enough. Oh so wrong for sure. The years have gone on, and his teenage years started. A huge situation of domestic abuse occurred and we were both hurt. Now for sure the marriage is over, we moved out to start our lives over, I had already had 2 more sons and it was us against the world. My first born is now my rock he was so strong through all this, he was the man of the house, we had no were to live and no idea where we were going. We stayed with my parents and then with my best friend, then into an apartment , then made the mistake of going back to my husband... The domestic abuse started back up and I had delivered the little boy I was expecting when I first left, and this time my son was even a victim. We fled I meet a great man and he gave me the strength to never look back, I've remarried and started over life has becoming so good. I have had another baby a little girl this time. Then my oldest son started having issues he suffered in silence, but became angry and argumentative, He was then admitted into the hospital for some help, it was horrible and scary. After following the doctors advice, and receiving the dreaded news, my son had a mental health disorder. Really why? Now I have one of the smartest kids I know with no dad in the picture and mental health issues, he is slowly falling apart, and school is making life worse. The bullying the hallucinations and the voices are the worst for him, I don't know how to help him and the medicine is not working. Low and behold he was done fighting himself and tried to take his own life.... Suicide was what he thought was the answer, my world was breaking. I immediately pulled him out of public school and took on the challenge of homecomings. Time progressed and he showed so much improvement, he is working and doing mentally better. Now he has decided back to public school he is going. The topper he is also ready to start seeing his biological father and put everything behind him. Im excited and even scared for him. In the meantime I am now the enemy.. Living one day at a time, focusing on him and the other kids. But never seeming to be enough.