For Over A Month I Have Been Extremely Tired, Irregular

for over a month I have been extremely tired, irregular periods, smells make me nauseated, thirsty and I seem to urinate a lot more. I am 45 years old and had my tubes tied about a year and a half ago. I took to pregnancy tests, both negative, and I am at the end of a normal acting period. What should I think about these symptoms? Is it something I should be concerned about?