Am i pregnant ?

Hey its nai 16 going on 17 me and my bf had sex on multiple occasions without protection and its been 3 weeks and ive been feeling nauseous and been getting really hot out of nowhere and i have been taking ALOTTTTT of naps . I think it was my period it was heavy but after 2 days it stopped and was brownish and light pink i took 2 test and both cane negative is it to early to know ?