You said you are experiencing more stress. Are you eating differently? Sleeping less? I lived with migraine headaches until 5 years ago. I had a stressful job, I had a newborn son along with a 3 year old. I was experiencing 25 - 28 migraines a month. What helped me most was getting off the migraine medication (probably not your problem). Second was getting 7 - 8 hours of good sleep. I know it sounds crazy but getting a restful sleep cut my headaches in half. Finally I started to eat less prepared foods (fast foods and boxed/canned foods) and added daily exercise.
Doing everything right I can go 6 months or so without a headache. When I get 5 - 6 hours of sleep my migraines return the next day. Take a look if your normal routine has changed due to your increased stress, if it has, try to make changes where you can.