This is not uncommon. This sensation is not new. You have always had this sensation except your brain ignored it. Once you hear it the first time, your brain develops a sensory index/memory of the sound and 'pays attention' to it more often than before.

This is no different than noticing how many people have the same car as the one you just bought. Your brain created a stronger index/memory of the car you bought and every time one drives by, your brain 'perks up' and acknowledges it.

These are also traits of anxiety.

My best to you.