Hi dot
Sorry to hear this - you have had plenty of advice about the dogs, but what about you?
Your reaction is physical shock. You receive a burst of adrenaline which enables you to deal with the situation, but as it disipates back through your bloodstream, you feel very faint, and dizzy, maybe nauceous.
You need to drink some strong sweet tea, and relax, sit in a chair and take some deep breahts, you will feel better.
There is no real fathoming of dogs' behaviour - it is usually a 'pack' thing, the 'under-dog' decides to try his chances with the pack leader - so be aware it may happen again.