Week late- negative blood test, what the?!

Elisha • TTC for 4 years. 2 MC, 3 tries at IVF all unsuccesdful- endometriosis and unexplained infertility
What is the deal?! Has anyone else ended up pregnant after a negative blood pregnancy test. I usally have a 26 day cycle, and am currently on day 32. Blood test 4 days ago showed a level of 2. Had verrry slight brownish discharge this morning but that is it. Husband and i have been trying iver 3 years- 3 failed IUI's and 2 failed IVF... looking for some hope here!