Some 25 Years ago your Grandpa told me that the peace symbol was negative and did not mean peace.
I was doing some research and found some info on it.
This symbol has been known as a Nero Cross and or a Teutonic rune of death used by Wiccans and Satanists in rituals. When you have a little free time you may want to google this and do some reading for yourself. If you still have the guitar strap with this symbol on it get rid of it for your own good.
I trust you are feeling better!! Love You , Mom