I haven't seen many people mentioning experiences with the implants in all my time here (the same goes with the shot/Depo Provera; most Litsters use the other forms of bc, it seems!), but a quick google search reveals there's tons of information elsewhere online. And, yes, it appears that heavy, prolonged bleeding seems to be a chief, terribly common complaint with this form of bc.
I'd suggest checking out the info you can find online in terms of experiences and the provider information/leaflet for the drug (drugs.com usually has a link to it) because it might give you a good idea of how common it is and what you might expect in the future. Then talk to your doctor if it's a concern because birth control should make your life easier and less worrisome, not the opposite! Personally, from what I've both experienced and read, I've come to the conclusion that we should mess with our hormones as little as possible. Semi-permanent/longer-term forms of hormonal birth control are FAR more likely to be problematic and should probably only be used as a last resort in most cases, IMO.
Anyway, I hope you find the answers you're seeking and get all of this sorted out!