I am so Lonely, Mum & Dad split, new home...

I never thought about it, you know? Signing up for this site, it never occured to me, but I thought I might aswell, since I have nothing left anyway.

I don't want to see any Doctors
I don't want any Medication
I just want myself back
Here it goes

Hello, I'm a 15 Year old boy, living a normal school life with some bullying a year back which has passed, it hit me quite hard, but overall I had no problems with.
Just recently my mum and dad spliting up, I have been strangely upset, even now I cry myself to Suicidal thoughts. Living only with my mum, because my sister and brother, who I loved very much, who I played Games with when I was a kid, I watched as their lifes grew even more perfect, before all this stuff beat up my mind, which I'm sorry I cannot explain. Once we got to our ''New House'' I had to make some new friends, at first I cried, I felt like I couldn't make any friends, but that was years ago, I now go to school and know alot of people, but none of the people I actually go out with outside from School, they don't see me as that kind of friend or classmate. After my friends pushing me too far, I lost them, as happy as I was to get away from those people, it hit me, extremely bad. I sit here, alone, just living with my mum on a summer holiday, I'm nearing the end of High School soon, my brother gives me the advice to leave Highschool with friends, but its just not the same. But I had a plan for the summer, its to be friends with my really old friends, these people are the nice people, we used to play games, go outside and play football, but this was 2 years since I last met them, luckily I'm still friends with one of them ( My best friend ) he kinda suggested I should be friends with them again. Even they said they are alright about it, they called me ''dead on'' which basiclly means I'm a nice person and such. So I'm basiclly all set, but heres the story if you don't understand
I was once friends with these nice people,
But as I made this new friend, he made me gradually move away from these nice people
After a bunch of arguements with this ''friend''. I decided not to be friends with him, thats where this summer comes in, I've lost my old self, all this happening at once, I have lost my personality, I lost my charm to make people laugh. I can barely look in the mirror anymore.
The original plan was to become friends with these guys again, and live a happy life once more, but I'm scared I will not be accepted.
I'm also worried my mum has lung cancer, but she is all I have left, and I sadly promised myself if she dies, I will have to kill myself. I'm so lonely here everyday with nobody to understand me. Can anybody help me?