Ive Been Really Paranoid About Being Pregnant Im Only Sixteen

Ive been really paranoid about being pregnant im only sixteen years old and i really cannot have a baby i started my period the 1st of this month i dont really know what my cycle is but im guessing its the average 28 days. I didn't really have sex. All me and my parner did was grind naked skin to skin on march 19 and 20. He didn't ejaculate but im still super paranoid. My period was suppose to come the 29th but instead it came on was 26th. It was lighter than usual it lasted for 4 days and the blood was bright red im scared thats its implantation bleeding and i cant really sleep or do anything because i keep stressing. Am i pregnant