BFP to BFN at 5 weeks

Ok, so 1 day before my missed period I had a nice dark line, which indicated pregnant! Even went to the doctor and took a test there and that came back positive. Today I started getting brown discharge and now the test is coming back negative. Part of me wonders if this is the ‘hook effect’, but I’m just not sure now! I went in today to have my HCG levels checked but won’t know for a couple days. Anyone else have the same symptoms and still had a successful pregnancy? My husband and I are grasping for anything positive.