Early signs or sickness?

I found out I was pregnant with my first two children at 3 weeks, so very early. I had no symptoms with my first and only slight nausea with my second. I’m currently 10 DPO and have had diarrhea and nausea all day long. I also had the same thing happen 4 days ago and was in bed all day, then the two following days I felt better but had a little nausea. Yesterday I felt completely normal, then today WHAM! It all came back. Could this be a sign of pregnancy or am I sick with something?