Emotions and sensations

If emotions are caused by a thought and can be felt in our body, do sensations start in our body and create a thought?  So for example I have a toothache (the sensation of pain comes first) and then a thought: I’ll need to see a dentist, then a feeling of fear.  What would be the C and the T causing the fear?  So, even though we may think that the fear comes out of the pain, there has to be a thought in between? Or can we have an emotion coming straight from a sensation?

How about a memory: Can that trigger a feeling? Is in that case the memory the thought?  For example in the case of a traumatic experience like a car accident. I’m sitting in the passenger seat and the driver isn’t breaking till getting very close to the car in front of us. Fear wells up as a response to a memory of a previous accident. Does the fear come out of the memory? Can that happen involuntary, without a thought?