Scared 😓

So my boyfriend and I had sex after my period. We did it a few times stupidly without a condom and with. Though he never cummed in me. It's been about 3 weeks since having sex for the first time this month. And it says my period is suppose to come in 5. I've been getting the normal cramps I get 1 week before my period. But today I felt a weird cramp/tightening in my lower stomach I've read that it's a pregnancy symptom. My boobs have also been really sore but that could be from puberty. I've read that precum can get you pregnant... is that true or a hoax? I'm just not sure of I'm overthinking it too much...