I Had A Tubal Ligation July 23 1997, I Have

i had a tubal ligation july 23 1997, i have not been sexually active in 5 years until this past nov, i was on birth control for 5 years to lighten my periods, my periods have always been regular and on time. i stopped taking birth control in sept and became sexually active in nov....i missed my jan period, im having dizzy spells and nauseua.....i turned 41 in dec... is this menopause signs or is it possible i could be pregnate?