i need help.

i’ve been on bc for about 6 day’s now (got on the 19) and i was supposed to get my period the 22nd but it hasn’t came. i have gotten cramps and what not but no spotting or nothing has popped up. i’m on Nexplanon(?) the implant that goes in the arm. i’m 17 and idk if this is normal or not. my arm was hurting severely to the point i couldn’t lift up a cup or let my arm rest (like walking with my arm touching my side.) i just need advice or something to calm me down bc i keep getting panicky. ty is anyone replies.