I wish I knew what, if anything, triggered mine. Those around know long before I do. I understand, in a way, the "odd" distant feeling you describe, but by then it's way too late. There's the feeling that something isn't right, but I'm unable to say what, or why. But might go no further than that. Always helpful when trying to say what's wrong.
What brand of sausage rolls do you use?
Aldi sausage rolls or pork pies but I've found Ginsters are very good when the nearest shop is a Spar!
To be serious I appreciate how fortunate I am to know and understand my triggers. Generally I get 20 - 30 minutes warning and eating inside that period is enough to prevent an event.
My last fit, when I didn't act quickly enough, was July 2011. A Friday night, I had driven from Knutsford (work) to Southport (to visit son) and then Chorley. I was tired, stressed by work and hungry. I bought a bag of jelly babies, which I ate, when I filled up the car. About 2 minutes after walking into the house I went down.
This resulted in my licence being "revoked" for 12 months. I had a daily commute cycle, train, cycle two hours minimum each way including 36 miles cycling for 12 months. The impact of this alone on life was very significant. I can't imagine how difficult life must be for anyone who doesn't know their triggers.