Sorry to hear you're getting the headachless migraine's. I often get aura's without ever getting the headache. I experience extreme mood changes, sound, light and smell sensitivity. I can also experience numbness in random parts of my body. Random nerve pain etc...the list goes on.
Many of my migraines (with or without pain) are triggered by stress, good or bad. It doesn't seem to matter and there is no rhyme or reason to it for me. I think that I have figured out that I need to keep my whole life consistent to have any success at harboring some control over this disease. I know there are some postings on this forum regarding positive stressers triggering migraine attacks, but I can't remember the posted topic.
I don't think i'm helping you at all. But at least you know you're not the only one. There are many of us that trigger the same way.