It has been happening for a long time now and I have no idea what it is, but I'm frightened that it could be something serious. The voices are very loud and mean.
Answers (1)
First I'll give you my personal opinion, just remember that I'm not a doctor.
You could be schizophrenic, the auditory type, which is the most common type of schizophrenia. This could be what you're experiencing, in that case I suggest you see a doctor, and talk about possible medication to see if that helps.
Now I will give you my spiritual opinion, I'm not trying to offend or scare you in anyway, I am a Christian, and it's been well known fact for a long time that spirits can send you hallucinations, as someone who is not an expert in this field, my best advice I can give you would be to pray to Jesus and ask him to take away these voices, this might sound like rubbish to you, but it has worked for a lot of people, both for Christians and non Christians.