Hi Adam
I know a guy that cluster headaches and I can attest that it doesn't look pleasant, when he has an attack.
Unfortunately, you're not going to find many clinicians who would entertain HRT at your levels. However, when you consider your neurological condition - if it is that - then there are options open to you.
1. Find a neurologist or specialist who may reconsider your T levels in light of the evidence from research for cluster headaches and testosterone.
2. Boost your own levels of T naturally.
3. Decrease testosterone E2 and SHBG conversion (HCG, or Clomid, or AI)
4. Try Forma Stanzol, which decreases conversion to E2 and increases testosterone. FS also lowers prolactin and will no doubt limit or eliminate SHBG levels too.
Whatever. There's a lot you can still do and nearly all options will likely get this sorted to some degree.
All the best.
Craig