Can you psych yourself out enough to create early pregnancy symptoms?

Breanna
We tried on leap day, haven't tried before or since (thought it would be cute to make a baby on a day that doesn't count) and since Wednesday (March 2nd) I've had pms on full blast and I don't typically get pms symptoms. If I do it's a few days before my period starts. In addition I seem to get wheepy over everything (and I HATE crying in front of people), and my nipples are so huge its like they are trying to swallow my piercings. Has anyone ever had similar symptoms and later learned it was all in their head? Am I crazy banana cakes or? 
* Sidenote: before last Monday I have never considered ever having kids and I honestly didn't think that we would get pregnant on the first go
Any feedback would be appreciated.