Probably the most common form of magical attack proceeds like this. It starts with waves of "sickness." That full-body tingling sensation you get from a fever. Uncomfortable waves of an undulating and destabilizing "sick feeling." This should proceed all day. Then, at night, the really bad ones will cause your thoughts to become stark and depressing. The goal is to get you to think about killing yourself. Dark as fuck.
The one rule about magic to remember is that ethereal energy can only influence. It cannot make the decision about how your reality unfolds. You are in 3d reality, therefor you decide how your reality will unfold.
If you feel you might be being magically attacked, there are a number of good techniques that will help you weather the storm.
1.) Laughter and Joy. This is the nature of polarity. It will cancel out the evil that is coming toward you. Fire and Ice don't make good bedfellows. One will kill the other when they meet. You are in control of whether you are laughing or joyful, so you will ALWAYS be able to decide which polarity kills the other in your own space.
2.) Shields with mirrors.
Play this on repeat. Dance to it, if it brings you joy.
3.) Ask Mother Earth for her permission first. Envision the negative energy coming at you as a line from them to you. Grab the line, sever it from yourself and thrust your end of it into the ground. This should have the effect of them missing you and draining all their energy into the ground, where it can be purified and recycled.
4.) Grounding with explosions. Do your standard grounding technique (Grow a root that goes miles into the earth and begin drawing up light energy). Draw the energy up in self contained spheres that go to the area of the body you want and then explode. This will have the effect of incinerating the negative and re-energizing your body..
Always remember. You determine the outcome.
You are far more powerful than they will ever tell you.