"On the day of implantation or shortly thereafter most women have usually no specific symptoms, no cramps or bleeding. However, some pregnant women experience cramps or a couple of drops of bloody discharge, so-called ‘implantation spotting’ about a week after ovulation.
Implantation spotting as an earliest possible signs of pregnancy is the exception, not the rule. Most pregnant women will likely not have spotting or cramps on the day of implantation.
There is insufficient scientific evidence to correlate certain early changes in the temperature chart, such as a dip (‘implantation dip’

, or a third rise in temperature ('triphasic curve') to implantation or pregnancy.
Many pregnancy fertility charts do not have typical temperature changes like dips or triphasic patterns. And many triphasic charts or charts with dips turn out not to be pregnancy charts.
Neither a triphasic curve nor an "implantation dip" are sufficient enough evidence that pregnancy has happened and it gives too many women false hope, while the absence of a dip or triphasic pattern can still mean that the woman is pregnant.
Among your best earliest possible signs of pregnancy is a positive pregnancy test or when on the temperature curve your biphasic temperature is elevated 16 or more days after ovulation without a menstrual period".