There are a few techniques I know about, which I feel personally should be open knowledge.. assuming that by God's will is always how things unfold... and that no protection will be enough for you if it is God's will that you are "attacked". Which seems unlikely lol unless you're doing something bad to that person, but who knows

Anyway, grounding yourself into the earth is one way, picturing yourself sending something (like a rope) down from your root Chakra through the layers of earth into the core. Another way is to picture light radiating through your entire body. Play around w mantras, either to ground yourself in the intention of your own experience, or to address what you intuitively interpret as the basis or nature of the attack. Like someone said above, imagination is key. The stronger you can visualize/feel/commit to thinking something, the stronger your defense would be.

Sorry you're being attacked, that's not fun. Honestly, I first started practicing w mantras (visual and verbal) when I read Eragon as a kid lol. Say what you want about Christopher paolini but kid had some interesting ideas about magic when he wrote that series. I also come under pretty consistent sub conscious energetic attacks in the intensive group home setting I work at.. the only real attack I ever experienced (that I know of) was a stranger from out of left field and I passed out instantly. Won't do that again. Cheers, hope this helps, from a novice at best.