Hi, My Period Is 13 Days Late. I Have Taken

Hi,

My period is 13 days late. I have taken 3 HPT and all were negative for pregnancy. I have been off birth control for 3 months and the first two months my period was regular. Comes every 30 days. I have never been this late. Since last week I have been nauseous and vomitting in the morning, nothing too bad. I have itchy breasts, metallic taste in my mouth. And I did have unprotected sex the days leading up to expected ovulation. Could I still be pregnant?