Not convinced..

I'm not convinced that I am not pregnant .. If I was Id only be almost 5 weeks. My period was 6 days late and I only bled for 1 1/2 days . My period is very normal (28 days) I had brown cm then went to dark red-red-brown within 1 1/2 days . I've been feeling nauseous the last couple days. I've taken multiple tests all bpn. Had a blood test done and still waiting on results. My lower back has been spastic. As well as lots of headaches and I'm exhausted even after 8 hours of sleep. I do know it's possible it's just abnormal period but the nausea I never get..