Amitriptyline was the 2nd med I had prescribed during the course of treatment for CH.  Of all the meds I have tried it was the one that I could least tolerate and although I had some of the "confusion" you mentioned, by far the worst side effect was waking up at night with both my forearms and hands "asleep" so badly that they ached.  In my experience Amitriptyline and Noritriptyline are both "old school" meds when it comes to CH. 

DD

I have taken 10 mg of Amitriptyline at night for 4 0r 5 years, which is a very small dose.  When I first started it, it made me sleepy.  The only side effect I don't like is mild constipation.  It was not given to me to abort or prevent clusters, but rather to ease some of the nerve pain and help with sleep...which in turn did help.  I cannot speak about it alone because I take it with other meds as well that I started at the same time.  My brother could not take it at all.  He had symptoms similar to what you describe.

I started Amitriptyline towards the end of a cycle and found that it almost totally knocked out the night time hits. I started with 25mg and found that was way enough and I'm a pretty large fella. I did not experience a lot of the side effects as some have experienced. I did experience strong sedative effects though and required at least 8 hrs (10 even better) of sleep and a large strong cup of coffee in the morning. I asked my doc to prescribe the 10mg and I sort of bounced back and forth between 10-20mg before bedtime. It helped me.

That being said, I was nearing the end of my cycle and had already been on a tapered dose of Prednisone, Verapmil, and Triptans for acute attacks (Treximet - 85mg Sumitriptan, and Sumitriptan Nasal Spray -20mg). The nasal spray worked the quickest. I ended up halving the Treximet and that worked ok also but took longer. The side effects of the triptans are certainly prevelant. For me it felt like I was having a slight heart attack but those subsided and were well worth putting up with to combat a 2-3 hr k9/10.

Midway thru my cycle I finally got setup properly with 02 (HI FLOW AND NON REBREATHER MASK) and that helped abort or at least lessen the length and severity of the attacks.

If your Doctor will not prescribe high flow 02 for a diagnosed Cluster Headache patient they should be reported to their governing agency for malpractice.

Next time the axe-man visits me I think I might try Melatonin for sleep instead of the Amitriptyline but I would use again if needed.

I've used amitriptyline as my go-to preventative for many years. But I get episodic clusters of 1-6 months at a time every 1-2 years. That may sound infrequent but when they hit they are relentless and unforgiving. I usually just hi-dose oral pred for few weeks while they elavil is "adjusting the receptors". I start at 100mg and usually go up to 150. First week I'm a little sleepy the next AM but for me elavil never fails. I've tried most all the other the other things w/o very good result but that's just me(I'm kinda weird anyway). So I know it's old-school but at lower doses it can work--but lotsa side effects. Hopefully you can try some of the other more friendly oral meds if the elavil is too rough. And yep that sumatrip dosing sounds way out there too-wow. Keep in mind I'm really not trying to give advice here, just telling you what I do! good luck.

Don't know about the meds but I have had some experience with choose & bodge,sorry book, keep trying on the net , try ringing them as that should release new appointments BUT if you get a cancellation make sure it's to see a neurologist. I ended up in an me clinic which was no help what so ever. Don't be surprised if you have a 3 month wait.
sorry it's not good news but it's the best I can offer.

try searching on line for the London headache clinic ,i think that's what it's called , you don't need a referral but they do charge £100 for a first appointment, tho i don't know what they are like , was a bit too expensive for me at the moment.

all the best
Nigel