can get a negative prgnacy test but still be pregnant?

Omega • my name is omega (Yes strange name) I am 18 and have a wider full boyfriend who is 44 we are not yet TTC but will be soon so cross your fingers!!!

my period started on the 6th of september i spotted about two weeks after my period and I had sex about a week after my period. And and I took a pregnancy test about a week after I was spotting. And and my period was supossed to to start around the first of October now it's the 6th so idk what's happening!?!?!