I had my period a week and a few days early. 9-10 days before my early period my and my boyfriend had unprotected sex. But my periods are never heavy but this time it was kind of heavy. And I've been cramping also. Is this a sign of pregnancy?

No. The first sign of pregnancy is normally a missed period. Sometimes women will have light bleeding instead of a period, but a heavy period does not indicate pregnancy.

That's not to say it isn't possible, anything is possible, but it's unlikely.