Hello, being over sensitive can come from your natal chart and your soul.
If you have an excess of the Water element in your soul. If you lack fire and have much water this will most likely cause you to be over sensitive.
Look your natal chart maybe you have like double or triple cancer (sun/moon/ascendant) or many planets in water and lack fire element etc this kind of things I just started learning astro so I can't help on the details here. Start learning some astro if you can it's really interesting.