!!maybe pregnant?

I am 8 days late for my period with just dull ache type cramps. I had unprotected sex ( not on pill ) a week later i had spotting just for one day. Then 2 weeks later my period was supposed to start but is late. My lower back is sore and I feel a lot more tired than usual. These are the only symptoms I have atm. Is there a chance i could be pregnant.