Help!

So my husband and I have been TTC for about 5-6 months now always getting negative after negative. Well this month is no different, EXCEPT AF is 10 days late! I've taken two pregnancy tests, one the day of my missed period and the other one just a couple days ago, both negative. AF is always on time and I've been having some pregnancy symptoms and been on and off sick all week, feeling nauseated and some of my favorite foods just not sounding good. Should I keep taking tests or I've been thinking about just going to the doctor and having a blood test. Any advice?