First off welcome to VT! I think your post is fine here. You posted it in the right spot.
Ugh I'm sure you feel like crap and that's expected after getting broken up with. But you have to realize that in time, you'll be able to heal and you'll be able to move on. It doesn't seem like that now but trust me, you'll be able to get out of your suicidal thoughts and depression. Life has it's ups and downs and you gotta deal with them and not just give up and kill yourself.
Hardships make us who we are today and make us stronger. You're only 15 and have a whole life ahead. Don't put it to waste. Trust me that it will get better. You just have to give time a chance. You have nothing to lose sticking it out. You'll be fine. I know you will be. We've all been there.