Why Am I Feeling Tired And Light Headed After Intercourse?

I had sex the day my period ended it started Mar. 22 and ended Mar. 26. Has sex on Mar. 26 late at night. Lately (the past week or so), I have been feeling tired, been cleaning a lot more, and the past two days Ihave been having a "in a dream" or lightheadedness feeeling. What could be wrong? Am I pregnant? People say I might be.