It could be as you say Baz, social anxiety for me probably has something to do with it. I can be at times, a little "socially inept" due to anxieties.

Would like to make an update.
Today I was able to use the work restroom, was lucky enough to time it right when another supervisor was coming on so I wasn't on a precise time constraint. The BM wasn't amazing, but it was something. When I got home from work today however, things really got moving, and it was w-o-n-d-e-r-f-u-l. The feeling of eliminating a weeks worth actually made me tear up a little bit during the process.
I have been having open dialogue with a co-worker who has a similar shyness, this may have helped today as we've been having this dialogue for a week or so now.
I also have been trying to listen to my body more and actually attempt the BM, even though a part of me says it will be a failure, sometimes it works out.