I understand how you feel. Not exactly, of course-but I get the general feeling of just wanting to sleep. All the time. And that sleep isn't restorative. That takes a toll, esp. at your age, when you feel added and unnecessary pressure to want to be doing everything. It can't be easy. I feel for you. I don't think there is just one thing going on. You know, one can't tease apart psychological/medical issues. It's all part of the same system. One thing is amiss, your entire body feels it.
Please get a sleep study. You need to know why you don't feel rested. Your general practitioner should be able to give you the information. Your iron levels should also be checked.
You are quite articulate and intelligent for 14. Any age, for that matter. Are you able to let your doctor know what's going on (without your mom in the room)?
*Please get a sleep study.* The fact that your sleep is not restorative means something is off. It also sets you up for all these problems. You need to know why you aren't ever rested. Once that is settled, I think everything else will also settle. It's better to know than to go through this torture. It won't hurt. You'll be observed sleeping, so it won't exactly be comfie, but you know that. And the benefits far outweigh what you're going through now.
You have your whole life ahead of you. You're obviously smart-take charge, get the answers you need, and the rest of this will fall into place. I'm rooting for you.