You can't do much against the hopelessness, negativity, and sadness. Over time you start to feel more and more this way. You just don't have enough willpower to withstand these emotions forever, and neither does anyone else. You can't control these feelings all the time, but when you can control them, you should try to do something against what makes you feel bad or do something that makes you feel better. You will fall down in life, but you can always get up again.
When I'm feeling down, I also get easier angry at someone, because I'm more irritated and say things that make people angry. And controlling this is hard since you act more intuitively socially.
So you spent all your time in bed? I hope you don't lie there doing nothing because that's not very enjoyable. I think it's best to distract yourself with something when you feel that bad. Playing video games, watching something, reading, listening to something won't solve your problems, but it can help to kill time until you feel better.
You probably shouldn't worry that much about romantic relationships. You are just 17(or 16). Almost all romantic relationships people have in high school won't last long. It's too early. There so many things you probably need to figure out before you are can have a serious relationship with someone. Most high school relationships start to fall apart after school because people move out, go to college or look for a job. At this point, when you begin to find your way in life, you have much more stability, which you need for a longlasting relationship. Also, do you feel ready for a relationship? You don't seem as you can deal with your own life. How would you be able to deal with two lives then? If you just need someone to feel not so lonely in life, any good friend should be able to help you.
I really don't know how to really help you either. Your problem is complex, and I don't know you well enough to understand it completely, and maybe you don't know yourself well enough either. My advice would be to keep going because things will get better eventually, and try what you can do when you feel better. When you feel down, you often think that things will only get worse, which isn't true. It won't be easy to fix your problems, but doing nothing isn't really a valid option either. At least you can try.
Sorry, that it took me two days to write a reply. I was "busy" procrastinating to socialize. I'm not perfect, either. Maybe you should take my advice with a grain of salt because I'm just 15 so I don't know everything, but I can relate to you.