What’s happening!?

So my period was late by 4 days as it’s never like that! Now my period has occurred it’s like a brown/red ish blood. I’m feeling really sick and I’m so sensitive to smells like I’m having a bath and being able to smell my dinner downstairs! I keep getting bad hip/back pain and bad migraines/headaches and it’s driving me insane!

I was so sure I was going to be pregnant but it seems to be going down a different path! Does anyone know what’s happening as my periods are never like this!