Thoughts? Help???

Just curious if the dip at 6 dpo could be implantation or just a fallback rise? Is one or the other supposed to dip below cover line (97.6)? No spotting. Typically have ovulation pains from O until AF this time pains were not one sided, I was nauseous, have headaches all the time, dry mouth & weird taste since 6 dpo.  No O pains today....which is so weird since usually go until AF!