Reading this, I can relate so well. I don't typically post on here much, but reading this I can't not reply to share a bit of my story to try and help because it sounds very similar to me.
I'm almost 22 as well, and when I was 19, I started to get a daily headache. That just started one day and got worse till I was in miserable daily pain, I had to drop out of school, and I couldn't do anything. I was constantly seeing doctor after doctor. They tried every test they could, they tried so many different medications. With no luck at all, it started to seem hopeless. I had doctor after doctor say I was a mystery and then give up on me. I got really depressed about it as well as I lost my life.
I live in upstate New York, and one of my doctors referred me to the Jefferson Headache Clinic in Philadelphia. It was there that the doctor was able to diagnose me right away, and figure out how to treat me and continue my treatment.
As for my diagnoses, I had a atypical migraine. I actually had something called Status Migrainosus. Which actually means a migraine that lasts over 72 hours, and what happens is that your brain gets stuck in a pain cycle and the usual thing that stops the pain cycle, isn't there to stop it so it just continues. The only treatment for it, is to be hospitalized and given a medication called DHE, which pretty much stops the migraine and makes things reset. And once you are out of the cycle that you are stuck in, they are able to treat it like a regular migraine. But when in a cycle, regular migraine medication doesn't work. Its a weird thing. I am lucky enough to have one of the doctors who knows a lot about it, who was able to realize what was going on with me and treat it. And I know I'm not a doctor, but I can't help but wonder if it the same for you. It might be worth looking into.
One thing I will highly suggest if you haven't looked into already, is going to a headache clinic, I don't know much about what is in the LA area. But they know much more about what is going on with headaches then other doctors, I spent a year and a half going through my primary doctor and a neurologist. Who were trying the right things, they ruled a lot of things out. But my neurologist at the headache clinic really knew a lot more about headaches and just all the more different types.
I know how it feels to just feel hopeless, but don't lose that hope. Just keep searching for that answer to get better. There is someone out there who has it, you just have to find them. And if you have anymore questions about what I went through, feel free to ask.