Can Pregnancy Occur After Tubal Ligation?

I AM 45 AND HAD MY TUBES TIED,CLIPPED AND BURNT OVER 20 YEARS AGO. I HAVE BEEN HAVING STRANGE SYMPTOMS. MY CYCLE ONLY SPOTTED A FEW DAYS, I EAT A WHOLE LOT MORE, I M USING THE BATHROOM A LOT, I HAVE A KEEN SINCE OF SMELL, AND I AM SLEEPING A LOT. IS THERE ANYWAY POSSIBLE THAT I COULD BE PREGANT?