What Are The Side Effects Of Implanon?

I have Implanon (inserted July 6 of this year). I am 22 years old, and it is the first form of contraception I've been on. For awhile, the only negative changes I noticed were some weight gain and more frequent, lighter periods that always last for about two weeks. However, more recently (over the past month), I've been having mood swings- I become irrationally angry, feel like bursting into tears for no reason, get impatient and irritated, have outbursts and say things I don't mean to close friends, and just feel generally anxious, worried, and depressed much of the time. I'm not usually like this, so I've begun wondering how likely it is that the mood swings are related to Implanon. Do side effects tend to appear like this, months after insertion? If so, do they tend to go away quickly, come and go, or persist for a long time?