Welcome to NT
That is quick. Reason to worry.
I've had 4 sets of EMGs. They're in a controlled environment. I would feel safe in saying they know what they're doing. Anxiety is understandable and I would be anxious before each set I had.
I won't last that long. You can tolerate it for a little while, in hopes of knowing what's wrong.
Sometimes it wasn't painful. Sometimes just a little discomfort. So don't be too worried about it being painful. It's tolerable, even the worst one.
I pray the EMG yields resutls that indicates the reason for it. Sometimes they are not conclusive. So just be prepared that it may not tell you exactly what's wrong. It may tell you what's NOT wrong with you, though. Can be used to "rule out" neurologic conditions too.
Keep us informed of how it goes.
I hope you find the cause and it's treatable.
Keep us informed.