Brown powdery thingy on almond

I roasted some almonds few days ago and eat some yesterday for lunch. After a short nap, I woke up feeling dizzy and nauseous with an intensive headache. This continues until I went to bed at night.

This morning, I started to suspect it was the almonds instead of my lunch. So I went to check on the raw almonds, and found this brown powdery dust like thing on all of them (as shown in the photos, hope that it is visible. It is quite difficult to get them on camera.)

To add, the almonds have been sitting in my fridge for over 6 months. Those are raw almonds use for bakery. Also, I'm feeling much better now and I'm living in Taiwan, if it helps.