Where you start is with the sleep disorder. When people don’t sleep, they are vulnerable to depression, mood swings, irrational crying and irritability. Please go to your doctor and ask for help with sleep. You might be referred for a “sleep study” to help figure out why you’ve never been able to establish a regular sleep pattern. It could be that you suffer from sleep apnea or some other medical disorder that is making it impossible to get a good night’s sleep. The good news is that it’s possible that a good diagnosis will lead to good treatment — which will lead to good sleep.
As for the relationship: You’re expecting a lot from a 15-year-old boy. You guys got together when you were only a little more than 13. That’s really young to find someone who will also grow into the kind of person who can be a forever love. You are changing. He is changing. It’s part of growing through adolescence. I’m impressed you two have been able to hold a relationship together in spite of your ups and downs and his inability to cope with them. He sounds like a good friend.
I doubt you are stupid. I think never getting enough sleep may make you look like you are. It’s hard to do your best academically or in life if you are tired all the time. For that reason, the priority has to be getting your sleep in order.
I wish you well.