ciao77,
A delay of a couple of weeks is not going to make a difference in the effectiveness of the vaccine. Now if you were several months off the schedule, that may make a difference, but even there it would not be too much.
Three doses (shots) are recommended over a six month period. The CDC recommends that the second dose be given one to two months after the first, and the third dose be given about six months after the first dose.
So, you should be okay getting your injection next week.
If you are concerned about it, discuss the situation with the provider who is giving you the injection. Good luck.