Hi ladies! I am new at this site and this is my first month TTC. I am on CD 27 and 13 DPO. Beginning to think I'm not preggers, but will wait until AF arrives (or not). I want to start charting my BBT or use an OPK next month. Any suggestions for the best thermometer or OPK to use? I'm brand new at this and don't want to mess up predicting my O day!