From your description it sound like a lot more than just migraines.
When my cousin was 21 she blacked out a couple of times while driving and had a couple of close calls. She did have a brain tumor which was operated on and she is doing fine 20 years later.
You may want to PM Karen and Barbara because they both have some experience with brain tumors and maybe can clue you in to some of the symptoms.
If it is Pet Talk nurses you are looking for, I'm pretty sure that Tatsxxx and Sirrahbed are both nurses.
I really think you should see a doctor soon and have more tests done.
Blacking out sounds scary, what would happen if you blacked out while riding one of your favorite horses?
Sending you some hugs and get well soon wishes.