I agree with all what has been said above. Diagnosis can be complicated and it can take a long time before getting there.
I have experienced it myself. As a lifelong "hardcore" migraine patient, I started to experience something that looks like cluster headaches 8 years ago during my migraine attacks. Around 1 hours of a sudden increase in very sharp excruciating pain around temple and eye together with autonomic symptoms and sudden restlessness. I found it all very weird as it was clearly very different from the usual migraine attacks. For a long time i thought it was caused by taking triptans but these bouts kept coming back in a vague "cluster like" fashion.
I did not trust the entire thing and finally made an appointment in the headache department of the university hospital here. After talking for 2 hours with the doctor and answering all kind of questions, he diagnosed me with cluster on top of my migraine and prescribed me oxygen. And thanks the man ever did that because oxygen is saving my life currently !!
My GP doctor still doubting the diagnosis... for him it is migraine and he do not believe migraine attacks can generate cluster events. So you see even doctors sometimes don't agree with each other. In July this year I had my second appointment in the hospital. Now I did my homework ... detailed headache diary, detailed reports of a few of these headache with detailed description of every symptom that appears every 10 minutes (that was hard to do during such a painful attack !) and after going trough all these materials and discussing again with their colleagues, the CH diagnosis was again confirmed. When my GP saw the diagnosis confirmation, he says he is still not convinced. They also give me verapamil but after 5 weeks of taking this, with their proposed doses increases, it did not do anything so I stopped it. I ask my GP if I should go for a second opinion in another headache clinic but he told me it will not make much sens as they will probably confirm the same. And as long as the oxygen does its work, why bother ?
In the meantime I have done a lot of research myself. Maybe they were confused with migraine with cranial autonomic symptoms which can be very tricky to distinguish from CH. Maybe I need more accurate data for my diagnosis. Recently I was reading on clusterheadaches.com that in rare occasions "migraine and CH can blend together in one" referring to a few studies that indeed seem to confirm my case. I also have the impression that the last two years, the migraine (which I have already since age 8) is getting weaker and the CH character of my migraine attacks is becoming more and more pronounced. So it is constantly evolving.
I have been very bad since May but now it seems to have stopped since 3 weeks. I started to take the vitamin D regime since 1 August so maybe that contributes, or it is just the end of a cycle.
So as you see, it can take time and patience to come to a diagnosis and maybe it will never be entire clear especially if you are a borderline case. Best what I can advise you is to collect as much as possible accurate data. Write down everything what is happening, all the symptoms with their start and ending times etc... Also film yourself during an attack. Your behavior can give a lot of info to the doctor.
All the best !
siegfried