does cramping means I'm pregnant??

I'm 3 days late, and I'm having a cramps, I dont have a pregnancy symptoms, I tested 2 days back, but it was negative. Could I be pregnant?? The last time I had sex was on August 7. And we use condoms and also not. But he never came inside me, and he peed and wash his penis off before having sex with me without condom. I have irregular periods, when I was A virgin I used to not have periods in a month, and it will come next month. But you know when you're not anymore, you would assume you are pregnant. I'm still not ready to be a Mom.  That is why I'm careful. But sometimes babies can surprise you. But I really hope I'm not pregnant.