Help!!!! Cycle changes

Steph

Has anyone else been as reliable as clockwork for years then all of a sudden here I am 1 cycle in since we went thru a vasectomy reversal Ttc #3 af came like 4 days early and has been much lighter and so far 2 days shorter than normal?! Come on! I started back in December taking a prenatal vitamin. Would that have such a drastic effect on my cycle?