How early was your earliest pregnancy symptoms?

Laycee
When was the earliest you experienced nausea when you were pregnant or symptoms at all? 
I've been very nauseous the past three days. It's been off and on, but mainly in the morning and at night, especially when I don't eat for a while. I didn't think much of it  until I was talking to my friend about how I've been so nauseous and that I may just have some weird mild stomach flu. Then my friend asked if I could be pregnant. 
I would only be 10DPO though... is that too early to have nausea? The nausea has gradually been getting worse but I still haven't thrown up even though there have been some close calls.