Can a negative test be wrong

Ashley
I need some advice ladies. I wasn't having my period so my doctor put me on pills to make it show. It came and went and about 3 days later I ovulated. My husband and I enjoyed ourselves those days. About a week later, I had brown spotting that started light, got heavy for a day or 2 and then stopped after 5 days. 
I am nauseous in the morning and if I don't eat at lunch which isn't normal for me. AF was suppose to come on the 4th but has not shown up. I took a test 2 days before she was suppose to show up that was negative and then took one on Sunday that was also negative. 
Any advice?!