Yesterday i had a severe blackout without nausea dizziness or pain. it lasted for a solid 5 minutes then was fine. should i be concerned?

Please get checked : By your family doctor. He or she should be able to find the root cause. Any blackout is reason for evaluation and should be taken seriously. Best wishes.

See your doctor: Blackouts aren't normal, and you state you have a history of dizziness, hypoglycemia, migraine and headaches. So, 5 minutes of a black out is 5 minutes too long, and needs to be further worked up by your doctor, or referred to a specialist depending on the findings. You do not want something like this occurring if your driving, or operating machinery that could endanger lives (yours or others).