A quirk I hope I can quit

I'm currently in my exams. Because this is my fourth time in a first year (university/college level, don't worry, I'm not that lost a case), I don't have to do a majority of the exams in the first semester.

During my first exam, I had noticed how the teacher kept glancing at me, suspicious about what I was doing.

I am unable to sit still, especially if I have to think, I look around, the ceiling, the windows, the door, anything to, for a little while, think about something else, so I can dig deeper for the knowledge I need.

At first, I thought this was the reason the teacher kept glaring at me, probably thinking I was trying to cheat during her exam. Another possibility is that she thought I was dreaming, only sitting there to waste her (and my) time.

However, today (more like yesterday, you know, Wednesday), during my second exam, I noticed I was whispering during my exam. Apparently, I am so badly adapted to the silence (I can't stand it, I really can't), that when the teacher threatens with a zero for whoever talks, I subconsciously whisper as low as possible. The sudden realization of my inability to actually stay quiet, opened a new possibility for the angry glaring during the first exam.

If I also mouthed the answers I was writing down to myself during the first exam, chances are the teacher thought that, not only was I trying to cheat and look at the answers of others, I had the audacity to help others cheat by (very silently) passing along my answers to the questions.

I can say with 100% accuracy that, if I indeed mouthed the answers as I wrote them down, I did not do so on purpose, but now that I'm aware, I'll try everything in my power to stop myself from doing it.

The looking around is something I won't be able to change, staring at the papers if I don't know the answer (yet) only makes me more nervous, and continuously staring at the same spot whenever I need to think, doesn't have the required effect, so I'll probably keep looking around, like I always have, so the teacher can see where I'm looking.

The mouthing, however, I need to stop. I don't know how often I do it, and which exams may or may not  have been influenced by my doing it, but if I don't want any more trouble during my exams, I need to find a way to stop it. If I don't, it will only be a matter of time before a teacher decides not to take any risks, and 'throws' me out, with a glorious zero on my report card.