My hbsab or anti-hbs result is "reactive" what does it mean? Do I have an hepatitis b?

No. The presence of antibody against hepatitis b surface antigen signifies that you are immune (protected) .
Hepatitis B. The result you have means that you are immune(protected against) hepatitis b. It signifies either recovery from hepatitis b or more commonly, the protection against hepatitis b as the result of receiving the hepatitis b vaccination seties.