On nexplanon since Aug last year. Had protected sex last month after period. He did not ejaculate. But I haven't had my period for July yet what's wrong?

Not sure . Exactly what is wrong but your nexplanon should over you for pregnancy . You could've having a slight hormone imbalance which occurs often at this age to account for the misses period. If worried. Check a home pregnancy test. Also remember the nexplanon does not cover you for stds.
Normal. When you are on Nexplanon, you will have irregular periods and some will not get periods as well. I hope you knew that prior to insertion. You may do a pregnancy test if you are nervous. Good Luck!