I had a similar experience, many years ago when I was 12 or 13. I woke up, got washed and dressed, then made my way downstairs for breakfast. On reaching the bottom of the stairs I awoke back in bed. I realised that I must have dreamt getting up and dressed. Feeling a bit confused I repeated my actions. This recurring dream repeated at least 6 times (possibly more) .Sometimes it was shorter sometimes longer before I awoke back in bed. Nothing was in anyway dream like or abnormal, but it was quite frightening at the time. I have never experienced this since that time, but for many weeks afterwards I half expected to suddenly awake back in bed .

As it was mentioned already, it's sleep paralysis. Maybe try to take some magnesium supplements to prevent it. This usually happens when you have too much stress in your life. If it happens again, don't try to wake up by force. Let it run its own course. Whenever I try to speed up waking up it's really bad. I feel as if my head was about to explode afterwards. I guess it's that sudden frequency you describe, I'd describe it as electric buzzing for me.
Yes, those were hallucinations, they are common with sleep paralysis. I only ever had them twice though.

You shouldn't feel shy or embarrassed about talking about it. It's an experience that happens to a lot of people, I've had it too. It is frightening because first you feel like your real body will never wake up and you'll be perpetually trapped in the dream state. And then you get the feeling of falling back into your body, waking up, but you aren't able to make your body work.
First time I experienced it I'd compare it to a wild amusement park ride: while on it it's scary but afterwards I wanted to do it again.

Are you taking any over the counter sleeping pills? I've had this experience happen to me too, but it was a long time ago and it hasn't happened since. It might just be something going on in your environment and it will pass soon.

Sounds like an out of body experience.

Also known as sleep paralysis. They're wack as hell.

Sleep paralysis