If you have had unprotected relations with someone then I am guessing you could be pregnant. You said it is too early. I think for the other ladies here you may want to give a little more info. I have never been pregnant, nor am I able to conceive. My DH and I are adopting so I am not the best for advice on whether the sickness last night may be pregnancy related or not but one of the other ladies may be able to help.
I just wanted to take a minute to say Hello and Welcome.