Although I haven't been officially diagnosed, I'm almost 100% sure that I have anxiety. I worry myself sick over the slightest things, think too much, have overblown phobias, experience attacks when I'm too stressed, I'm irritable, have muscle aching and weakness, lose sleep, and more recently, live with the constant feeling of being followed.

It started shortly before my high school let out for the summer. I began hearing a male voice call my name at random, and would feel someone poking the back of my head/neck. There was also the occasion when I would see a black shadow move out of the corner of my eye. It eventually manifested itself into the feeling of someone standing behind me. I still have it, almost constantly. I either sense someone standing behind or beside me. I'm lying in bed as I type this, and it feels like they're standing beside my bed, staring at me.

After about two weeks of losing sleep over this paranoia, I had a bizarre nightmare. In it, this tall, black figure was standing beside my bed, whispering ominously about how he's "always lingering over my shoulder" After waking up, I took to my computer and drew what I now believe this hallucination to look like. While I've never outright seen him, whenever I look at where I believe him to be standing, my eyes almost try to make out his image.
SIDE NOTE:This also happened before I had that nightmare, so it isn't a visual matrix or anything of the sort.

I decided that my method of coping should be to ignore him. I even decided to call him for what he is, and named him Anxiefy. I can also feel the air where he is change. For example, whenever my dad starts to act like a jerk (which is often), I can feel the air behind me become more charged and agitated than usual.

My point behind all of this is basically, is this normal? Do anxiety sufferers usually hallucinate to such an extent? Or am I just losing my mind?

I've attempted to attach the picture I drew of Anxiety, though I'm not sure if it worked. I'm no artist, I'm sorry. The white lines in the middle of the head are supposed to be hair.