Has anyone had symptoms 2-3 days after conception?

I think I'm going crazy but I'm having symptoms. My fertile days started on 3/23 and my husband and I got busy on 3/26 - 3/28. On the 28 I started to feel cramping, extra tired and nauseous ( I still do). I've never felt this mid cycle and also had a really bad headache on the 28th. My body just feels funny.
 I'm expecting my period on 4/11.
Just wanted to update that I took 2 test today and got a faint line on both.