Chemical pregnancy

I had a very emotional cycle. My cycles usually run 26 to 27 days. Well on day 29 tested and it was negative. I thought hmmmm since I still nurse Joey at night then maybe it is delayed. I spotted on cd30 so I thought af was coming. Then on cd 32 I still hadn't started and lo and behold a weak positive! I figured I o'd late. We only did it on the weekends cause who has time for sex with three young boys anyhow? I was mystified. How does this happen? When you are not trying right? I had 5 more days of positives and on the last day, today, it was definately coming up weaker still and poof...it was gone. I had just come to terms with the idea of another one and now I have to mourn another loss. I have told myself it wasn't meant to be and that there must have been something wrong with this baby. You know, the usual stuff. Then why do I feel so crappy? This has been a very stressful week.