The colored speckly spots you describe are called an 'aura' that is associated with migraine. Blacking out can happen, but you need to inform your doctor. Are you currently taking any preventative medications for migraine? As you know, blacking out while driving or working with machinery could cost you your life or the lives of others.
Has your blood pressure been evaluated lately? I'm wondering if it suddenly gets high, inducing the blackouts. I'm no doctor, you really do need to see yours. There are a lot of medications out there to help migraine patients now and you shouldn't be having to suffer every single day with a headache. If your blood pressure runs high most of the time, you may need to be on medication for that.
I understand that you want to keep at your job and you should be able to, but if you aren't honest with your doctor, he cannot help you appropriately.
Is it possible to see another doctor if your usual one isn't very tuned into migraine problems? Stress can help trigger migraines, but it isn't what's causing them in the first place. Have you been evaluated with and MRI or EEG (electroencephalogram of the brain) to see if you have any problems that could be found that way?
Having had migraines for over 30 years myself, I understand what you mean about it interfering with family life. Here's hoping that things get much better for you very soon!!
Take care ~ Renee
"Do what you can with what you have where you are."
- Theodore Roosevelt