Pregnant?

So I’m 16, my boyfriend and i had sex more than a week ago. My period is 3 days late and still hasn’t arrived. i went to the hospital two days ago for something different and they made me take a urine test and i was not pregnant. But I’ve been having these weird symptoms as if I’m pregnant. i keep having cramping which i usually have the day before or of my period. But instead i have cramping with no period. Is it possible that I’m testing too early? If so how long should i wait to test again? Thank you to whoever’s reading this lol.