soooo help!

I made an appointment with my obgyn to get blood drawn for pregnancy cause my period was late and I know blood can be more accurate than a urine test . she called and asked if I have taken a home test I told her yeah but the line was very very very faint and she put me down for a new prenatal appointment but I just took a test today and there was no line at all I don't want to go to my appt tomorrow and look dumb when it's negative what should I do? should I just go and get the blood taken anyway or cancel?