Thanks for your query.
You will not have periods post implantation
Cramps with bleeding per vagina indicates abortion
If you did not have any bleeding then it is not a emergency thing according to my knowledge.
is quite normal thing in first trimester.
But it is advisable to visit your obstetrician once.
Hope I have answered your query.
I will be available for your follow up queries if any.
Wishing you good health.