Missed periods

I’ve missed my period for nearly 1 month in a half and I’ve been sexually active with my bf he admitted to me he didn’t pull out twice in different occasions and I was fertile on one of those days and I’ve been feeling sort of sick lately and I haven’t put much importance but I really don’t know if I should take a pregnancy test, since I don’t have a regular menstruation. And i has happened to me before and The past time I did take a pregnancy test and got a negative result and my period was just late. And this time it way by far late I have no clue if I should just go straight to the doctors?