"If you're an anxious person anything can cause anxiety, but usually it's the other way around."
Absolutely!
Anxious people are almost always super hyper aware and focused on ANY sensations, and if anxiety starts creeping up, they will begin to catastrophize that sensation...with "what if" thinking, which causes the anxiety merry-go-round to just spin and spin.
The best thing to do is to try not to get "stuck" over thinking something as normal as gas. Dismiss the worry and get busy with life.
If you're an anxious person anything can cause anxiety, but usually it's the other way around.