Paranoid?

Okay so my boyfriend and i have never had unprotected sex and he has never even came while inside of me even if he’s wearing a condom. We only started having sex about 2.5 months ago and i’ve had my periods consecutively for the past 3 months. my period this month was almost a week late, but i still got it... my boyfriend made me take a pregnancy test 2 months ago and one last month after my periods ended and both came out negative. i told him there’s almost no way i could possibly be pregnant but he doesn’t believe me. he thinks i could still be pregnant. i have gained 11 pounds since the beginning of september and this is the main reason that he thinks i am. the day before i started my last period i spotted for the first time in my whole life, but spotting is normal for beginning a period. i’m also thinking the reason my period was later than it had ever been this month is because i’ve been so stressed out about “being pregnant”. opinions? we have talked about this almost every single day and it doesn’t help that i’m being accused of being pregnant when there is a super small chance... what do you guys think?