I have a implanon in my arm and it expired and i had sex last night and now i spotting could i be pregnant ?

Not impossible...: Implanon doesn't stop working the day it expires. There is a short grace period built-in. Of course, you shouldn't rely on this. Use a back-up method and have it replaced or switch to a different method. If you are concerned that you are pregnant, you can do a home pregnancy test. The spotting may be just be a sign that the implanon is wearing off. Best wishes.