Temp drop..what does it mean?

I'm 7 dpo, and on 5 dpo, my temps dropped quite a bit, then came back up yesterday on 6 dpo and are still up. This is my first month charting and I'm not sure if this means anything. Could someone look at my chart and tell me if it does mean anything, or it that just happens sometimes. Thanks!

Jessica

http://www.FertilityFriend.com/home/20eed