Am I pregnant?

Okay so I know it’s very unlikely, but I had my last period and I ovulated around the 28th (so my calendar says- I can’t track it well Personally) I have been having headaches the last week and I have been nauseous here and there and dizzy! As well as dropping things and the last two days- food that I eat regularly and never have a problem with have given me heartburn. I am supposed to start on Monday. What do you guys think?