I'm sorry you're meeting so harsh times about this. It's good to hear you have made friends at the boarding school - and really: You did something wise when thinking of contraception too.
I am not familiar with how implanon works! Only a few days ago a new forum opened though, Birth Control (contraception) >>
http://www.medhelp.org/forums/show/260
Maybe there are others who knows? You can find information about it one or another way on internet but be careful believing everything you read. It's a lot of information, and when someone share about how drugs work, the side effects are usually the first that's brought up - not saying anything about the rest of their health, co-ingestion or other important matters when it is about an intake - or use.
Maybe even the Thyroid Disorder forum could offer you some help too? I'll at least give you the link! >>
http://www.medhelp.org/forums/show/73
Don't hurt yourself to loose weight (please?). One of the first things that are done if you tell your healthprovider about feeling sad or depressed, is a little bit of bloodwork to see how your thyroids are working.
Remember that depression can happen to anyone. It's many things that act in....
Florena