am i pregnant or sick??

Hi all, I have a question to ask.
I have irregular period. and i just got married last year 27/11/11 and our unprotected sex starts on 1/12/12(first night). I am an indian.

I suppose to have my period on 5/5/12, but it came on 8/5/12 and it's very very light, even my tampon don't get dirty. it lasted until 11/5/12. I had my UPT test on 12/5/12 - result negative, then on 15/5/12- result negative too.

What's wrong with me? I am not sure. I sometimes have some sharp poking pain at my chest area, breast and abdomen. recently i had some period like cramps. and sometimes the cramps only focused on my lower left abdomen area. Is it a decease? Please advice me on this.
thanks in advance.