Just Visiting from another board..Pregnancy or AF Question

So I went to New Hope for a consultation on Saturday and they did a blood test called me yesterday and said I had a Beta of 5 and thought I might be pregnant!? This seems impossible Because I have already had 4 IVF tries, one that got to retrieval 2 cancelled (poor responder)and the last ended in an iui. Today I feel period-like cramps (Ive been cramping since the IUI I had almost 2 weeks ago (Thursday is my testing day). Do period cramps feel differnt from pregancy cramps, and isn'a a Beta of 5 the lowest it can possibly be? i think if I remember correctly he said my progesterone was a 19.