PLEASE HELP omg please

Okay so I lost my virginity last week, and I've been getting red brown blood spotting. It's not heavy. But I'm really worried. My boyfriend think it's implantation bleeding, we used a condom and he didn't cum but the condom was a little loose around his penis but the band was tight around his shaft. I'm supposed to be getting my period April 12 around there but I toke a pregnancy test yesterday and it came out negative. But I'm still very worried, please help. Mind you this was my gist time having sex. I asked my friends they said they didn't get spotting. I'm too young & very nervous please help