I Am 43 Years Old And Have A 28 Day

I am 43 years old and have a 28 day menstrual cycle. My last period was on January 31,st and have missed my period by over 5 days. I only once had sexual intercourse where my partner ejacuated out. Could I be pregnant or could this be premenopause symptons. I am getting the same PMS symptons but they come and go, but am not getting my period yet. Please let me know, what could be the chances of me being pregnant with all of above