Uh huh, yeah......
And if the petrified piece of wood doesn't work, try ceasing and desisting any and all thoughts about this person.
Now it is possible that you are simply delusional, and that it's all in your imagination. If you are not delusional, or just someone suffering from an over active imagination, than apply the above, and put the person from your thoughts.
People can not gain access to us, our consciousness on any level, or our vital energy, unless we allow them to. This can happen in a number of ways. Firstly, by fixating upon the person. Thinking overly about another can very easily create a link between the two of you, and allow that person access to you.
Fear, hate, anger, love, all these things can also open you up to another persons manipulation. Psychic self defense is on of my areas of expertise, trust me on this, I know of what I speak.
I suggest you visit youtube and type my name Magustaus01 into the search function. I have a video there on psychic vampires. While specifically addressing your problem, the solutions are the same, and quite simple. They also don't require the hauling of dried petrified wood into your home, a bonus. Simple almost always works best, as does that which is practical, real, sensible, and that can be explained in a reasonable rationale manner.
Such things as you are experiencing are indeed possible, but it's more likely your imagination, or your mental health, hard to say given as I don't know you. Anyhow, watch the vid, and you'll know a lot more insofar as what you can do to defend yourself against such people. The methods for defense against psychic vampires are more or less the same for the problem you are having, do not doubt. Feel free to contact me directly if you have any questions. Good bye, and good luck.