Possible pregnancy???????

Ok for starters I've had a tubial ligation almost three years ago. Have had a normal regular period starting about 4 months after I had my daughter. Everything was fine good to go, no complications... Until now. I am currently 15 days late an am freaking out!! Nothing has changed in my diet, exorcist, job, homelife, love life, nothing. Should I get checked for a possible pregnancy... And if do what would the health risks be for a pregnancy following a tubial ligation?? HELP!