Have you had a sleep study? There are several sleep disorders that can trigger early morning migraine attacks. I used to wake up with migraine attacks almost every morning until I was diagnosed with sleep apnea. Once I started using a CPAP every night, those morning attacks almost completely disappeared. It's worth the time and investment to know because the treatment is completely drug-free.
https://migraine.com/blog/is-snoring-giving-you-a-headache/
You might see about getting saliva testing for cortisol levels. This type of testing is usually done by a Naturopath. Mine sent me home with a test kit. I took saliva samples at four different times during one day then sent the samples in for testing. The results were sent to my naturopath for evaluation. Based on the results, he recommended adrenal supplements to restore proper cortisol production. My problem was related to fibromyalgia, not migraine, but any chronic pain problems can cause an over or under-production of cortisol.
https://migraine.com/blog/let-down-migraines/
The other thing to look into would be Melatonin. This is a hormone that is naturally produced as a part of the body's sleep-wake cycle. If you find yourself getting out of a regular sleep schedule, this might be something to talk to your doctor about.
https://migraine.com/blog/melatonin-effective-for-migraine-prevention/
Tammy