Is it possible to feel pregnancy symptoms if you're not pregnant?

Angela • Watchin` the wheels
I had sex two days ago with my boyfriend on the day I was ovulating. He pulled out, but now I'm freaking out about being pregnant. I have a two year old daughter and I recognized the symptoms then, but not until a few weeks after conception. I'm feeling nauseous (evan though my stomach is often upset in the morning) I keep feeling cramps (but pretty sure I was just gassy!) This happened less than 48 hours ago, is it evan possible to have pregnancy symptoms yet? I know I can just go out and get a test but didn't want a false negative if it's too soon to take. Anyone else mistake the stress of becoming pregnant for symptoms?