They both have a drop at 4 dpo and goes up again 5 dpo. If this trend continues and last month's was negative, should I expect a bfn this month??
I don't think so.
FWIW, my 1st pregnancy chart looks nothing like my second pregnancy chart. My 1st was triphasitic (sp?). My 2nd pregnancy did not look like a pregnant chart (except for the fact my temperatures never dropped below the coverline and I never got my period).
Keep hoping :)