Rant/ Overthinking?

I am angry right now. 1 my mother and I got into an argument and so I went to talk to my BF. 2. When I called my BF he didn't pick up after a couple of calls then after another call it goes straight to voicemail..... Why? 
Could he have turned it off? Or did it simply die? ALL I can think about is how his new "gal friend" that I've had problems with in the past lives in the same town as our school......
I think I'm overreacting but idk how to stop!  
I honestly HATE thinking that he would do something crazy but no matter how many I love you's I get, sweet kisses, and respect, I can't help but think about the most craziest things.