Hello, and I hope I can help you today. Having a procedure like an abortion and an Implanon insertion can certainly make you weak from the stress on your body. Feeling a headache and muscle aches can happen from being tired and dehydrated, and is unlikely a complication of the procedure or a side effect of the Implanon. You also may be having hormone fluctuations after the pregnancy hormone levels drop that may have triggered a migraine. So I suggest you lie down, dim the lights, take a pain reliever (whatever you normally take for headaches, like Tylenol, Ibuprofen, or something similar)) and try to rest. Drink lots of fluids and try to sleep. Most likely, you will feel better after some rest. Signs of infection include fever, foul smelling vaginal discharge, worsening low abdominal pain, and heavy vaginal bleeding. If you experience these symptoms, you should call or visit your healthcare provider. I hope I was able to adequately answer your question today and that this information was helpful. Best wishes, Dr. Brown