Opening your Third Eye is not always a bad thing. Having a sight can be rewarding. Like any gift we as humanity have, they can be a strength if we exercise it and learn how to direct it. The few experiences I've had of a very open Third Eye led me to see a few disturbing things, some of which were connected to the old house I was renting at the time.
With a little bit of light personal shielding work, an "exorcism" for lack of a better term of this entity who I was made aware of that liked to creep up in my tea ceremonies, and a crystal grid, I was far more comfortable. I still have some very.....spiritual dreams shall we say, but accepting that there are disturbing things is a lesson we all learn eventually.
Opening your third eye too much can bring an imbalance, which though the obvious remedy to your distress would be to close it, but why not try to develop other weaknesses or parts of yourself to be stronger than the visions? Build yourself up to find balance rather than bring down?
The grinding I used used rail spikes (convenient because I had an old train track maybe a mile from my house) but large nails could work too. I will get the grid up later this morning when I can get my book out from my bag.