Nexplanon?

I have an appt for nexplanon in late november, ive been on the pill for two years and recently ive been getting cramps when i never have and for some reason i keep forgetting to take them by a couple hours. Probably stress of college. But i just want to know all the opinions on the arm implant. And if i should try to stick with the pills. Or which protects more. My cousin has it and hasnt had a period for a year, so in that case how would you know if you were pregnant? I just have a lot of concerns/questions. Any advice would be great!