A while back I made up a spell for the physical plane in case I was ever attacked, it goes "Gracious Goddess please help me, please increase my strengt times three." I've used it in dreams, and stuff, but with that thing that's been following me. Should I use it if it attacks me any where? Physical, dream, astarl. I just found out that my head phones, I use them to AP, are magicaly missing. I haven't been home all day and left them in my CD player... So, I don't know if two things are at war because of me, because headphones don't disapear magicaly...
I don't see why you couldn't use this if something happens. If, when you say it, you feel protected and safer, then definitely!
There really are no straight and strict rules in psychic protection. You need to use what works for you. If this feels right, use it! :D
The best way is to not think about negs/attacks/astral combat at all and you will not attract this kind of events.