I'm so nervous and stressed :(

Okay first of all I'm going to start by saying I'm 16 and NOT trying to get pregnant.. This is long but okay my last period was August 18- 22...I had sex for the first time sept 6, then again the 13, 14, and 20(all protected/condoms).. The week of  the 15- 19 I was supposed to have my period , but it came a week late so I got it 22-26... Then I had sex the day after period sept. 27.. He had a condom on but it came off, didn't ejaculate inside of me) ...Got paranoid cause I was having cramps and a little spotting and took a test sept 28, came back negative. According to this other app on my phone ... I'm fertile this week.. But I'm not having sex anymore until I can tell my mom to put me on birth control .. I'm just so scared .. I don't know if I could possibly be pregnant or not , I've been crying myself to sleep and praying every night that I'm not pregnant ... I'm so stressed , and my boyfriend is pressuring me to tell my mother so we can be safer but I just know her reaction is going to be a bad one :( someone please help.