Late but -hpt

So I'm about to be a week late with my period. I have taken two pregnancy test and they were both negative at about 3 days late. I already have a son who is 5. I didn't know I was pregnant with him until I realized I was a month past due with my period. I didn't feel pregnant or have any pregnancy symptoms and it feels that way again. Even being a month late with my period when i was pregnant with my son the first pregnancy test didnt even come out clear. Can anyone relate? Maybe I'm just looking for opinions or any advise. I have an appt made for Monday with my Dr.