Can you get the morning after pill, the same day as the implant. ?

Sure: They are both Progesterone ( in the case of plan b) or ru486 is a temporary Progesterone blocker; in either case, you won't overdose. A pregnancy test is done prior to the implant and if negative there is an assumption you are not pregnant. Might wanna try to use the emergency contraceptive or morning after pill sooner if possible, to avoid a delay in getting the implant.