I AM RIGHT TO THINK IF MY GIRL FRIEND IS CHEATING IF SHE GUARDS HER PHONE ALL DAY,AND TURNS THE RINGER OFF?

OFF AT NIGHT? SHE IGNORED ME IN FEB FOR THE WHOLE WEEKEND AND ON SUNDAY I SAW A GUY DROPPING HER OFF AT HER CAR AT A RESTAURANT, SHE SAID IT WAS JUST SOMEONE SHE KNEW FROM A LONG TIME AGO. THAT SHE HAD GONE THERE TO ME ONE OF HER GIRLFRIENDS. SHE NEVER SHOWED UP AND SHE RAN INTO HIM AND JUST HUNG OUT WITH HIM AND SHE WENT TO ANOTHER BAR FOR ANOTHER BEER, THAT IT WAS NOTHING.. I JUST CANT GET OVER THAT. AND I DONT BELIEVE HER..AM I WRONG TO END IT OVER THIS